New Genus and Species of Erythraeinae (Acari: Erythraeidae) from ...

New Genus and Species of Erythraeinae (Acari: Erythraeidae) from Mississippi with a Key to the Genera of North American Erythraeidae W. CALVIN WELBOURN1 AND ORREY P. YOUNG2

Ann. Entomol. Soc. Am. 80: 230-242 (1987) ABSTRACT A new genus and species of Erythraeinae (Acari: Parasitengona: Erythraeidae) is described from larvae parasitizing Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae) and other arthropods in Mississippi. The active postlarval instars (deutonymph and adult male and female) are described from reared individuals. Bochartia shirleyanneae McDaniel and Bolen and Erythraeus whitcombi Smiley are transferred to the new genus. Paraphanolophus Smiley is transferred from the Smarididae to the Erythraeinae. The terminology of Grandjean is reapplied to the Erythraeidae. A key to the active instars of North American Erythraeidae is provided. KEY WORDS

new species, new genus, key, Lygus lineolaris

THE ERYTHRAEIDAE (Acariformes: Parasitengona:

Erythraeoidea) is a large and diverse group of mites with five currently recognized subfamilies and 40 nominate genera and subgenera. Four subfamilies (Erythraeinae, Callidosomatinae, Balaustiinae, Leptinae) and 12 genera have been recognized from North America. The Erythraeinae is the largest subfamily, with 19 nominate genera and subgenera worldwide, except Antarctica. In North America the Erythraeinae are poorly known (Southcott 1961), with only four genera recognized: Augustsonella Southcott, Erythraeus Latreille, Erythraxus Southcott, and Tepozatlana Hoffmann & Mendez. Another genus, Paraphanolophus Smiley, originally placed in the Smarididae (Smiley 1968), should be transferred to the Erythraeinae. Five of the 11 nominate genera (Callidosoma Womersley, Charletonia Oudemans, Caeculisoma Berlese, Abrolophus Berlese, and Hauptrnannia Oudemans) in the Callidosomatinae have been found in North America. The Balaustiinae is represented in North America by Balaustium Heyden. The single cosmopolitan genus, Leptus Latreille, of the Leptinae is widespread in North America. Systematic work on the Erythraeidae, and Parasitengona in general, has been hindered by the partitioning of their heteromorphic life cycle into a parasitic/dispersing larval instar and predatory postlarval instars, making it difficult to identify larval and postlarval instars of the same species accurately. Despite the lack of systematic work in North America, some erythraeids have been reported attacking economically important pests (Reinhard 1926, Essig & Michelbacher 1933, Loughton et al. 1963, Smiley 1964, Whitcomb & 1 Acarology Lab., Dep. of Entomology, Ohio State Univ., Columbus, OH 43210. 2 Southern Field Crop Insect Management Lab., ARS-USDA, P.O. Box 396, Stoneville, MS 38776.

Bell 1964, Struble 1972, Moser 1979, Houseweart et al. 1980); more frequently they are either misidentified or ignored. Welbourn (1983) summarized the current knowledge of erythraeid and other nonchigger trombidioid hosts and prey. Examination of erythraeid larvae from Mississippi parasitizing insects and arachnids obtained by sweeping or vacuuming the margins of roads, cotton fields, and woodlots revealed a new genus and species of Erythraeinae. Rearing of engorged larvae to deutonymph (DN) and adult stages allowed comparison of larval and postlarval stages with other named Erythraeinae. A new genus, Lasioerythraeus, is erected with L. johnstoni n. sp. as the type, with all active stages described. Bochartia shirleyanneae McDaniel and Bolen is transferred to Lasioerythraeus, rediagnosed, and measurements are provided for the prodorsal sclerite and legs. Erythraeus whitcombi Smiley is also transferred to Lasioerythraeus and rediagnosed. A key to the genera of North American larval and postlarval Erythraeidae is provided. See Young & Welbourn (1987) for information concerning the biology of L. johnstoni. Most of the chaetotactic terminology used for the Parasitengona consists of specialized terms invented for a single taxonomic group (i.e., Erythraeidae, Hydracarina, and Trombiculidae). For the Erythraeidae, Southcott (1961) introduced terminology consisting primarily of terms for the leg chaetotaxy, but this has not been widely used outside of his own work. We will use the general terminology developed by Francois Grandjean because of its much wider use in the Acariformes and the prior application to the Erythraeidae and its sister group, the Smarididae (Grandjean 1947a, b). Table 1 presents a comparison of Southcott's terminology for the legs of the larval instar with the terminology used in this paper. Measurements of the prodorsal sclerite (scutum

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Table 1. Comparison of Southcott's leg terminology with the terminology used in the current description Structure I. Unspecialized setae Normal seta 11. Specialized setae Genu (Ge) Solenidion (-ia) Microseta Tibia (Ti) Solenidion (-ia) Microseta Companion seta Tarsus (Ta) Solenidion (-ia) Famulus Eupathidia Dorsal eupathid Subterminal eupathid Companion seta Companion seta of h

Notation

Reference

Southcott (1961, 1966)

n

Robaux(1967)

Scobala (Sc)

a

k

Grandjean (1935) Grandjean (1947a)

Solenoidala (-ae) (SoGe), (Spinala) Vestigiala (VsGe)

k da

Grandjean (1935) Grandjean (1947a) Grandjean (1947a)

Solenoidala (-ae) (SoTi), (Spinala) Vestigiala (VsTi) Companala (CpTi)

f

Grandjean (1935) Grandjean (1935)

Solenoidala (-ae) (SoTa), (Spinala) Famulus Spinala (Sp) Spinatarsala (SpTa) "Sensilla alongside pedicel" Companala (Cp) CpTa

fp

Grandjean (1947a) Grandjean (1947a)

z

Grandjean (1947a)

ft

of Southcott and other authors) follows the standard measurements and signatures of Robaux (1974). Differences in Southcott's signatures for the setae of the prodorsal sclerite are: AM is ASens; AA is SBa; S is PSens; and SB is SBp. The distance between both pairs of prodorsal trichobothria (S and AM) is recorded as ISD. The prodorsal sclerite in the postlarval stages (referred to as "crista metopica" in the literature) consists of two parts: a thick, heavily sclerotized medial ridge, usually connecting the anterior and posterior pairs of trichobothria, and a lateral sclerotized portion. We will use the terms prodorsal sclerite to refer to the lateral portion and crista metopica for the medial ridge. Larval diagnoses include several abbreviations that need to be defined. First is the formula (f) for the number of normal or barbed setae (n) on each leg segment. For example fnBF = 4-4-3 indicates that the basifemur (BF) has four barbed setae on leg I, four barbed setae on leg II, and three barbed setae on leg III. Specialized setae such as solenidia, microsetae, eupathidia, and the famuli are not counted in the fn. Solenidia on the legs are summarized by fSol = 1(0-1-2-1), 11(0-0-2-1), 111(0-01-0), where the roman numeral indicates the leg. Because solenidia can be found only on the femur (Fe), genu (Ge), tibia (Ti), and tarsus (Ta) in the Parasitengona, only those segments are indicated in the formula. In this formula leg I has no solenidia on the femur (absent in all Erythraeidae), one solenidion (a) on the genu, two solenidia (4>) on the tibia, and one solenidion (co) on the tarsus. Microsetae (k), which are found only on the genu and tibia, are summarized by fk = 1(1-1), 11(1-0), 111(0-0). The number of eupathidia (t) on the tarsus is summarized by ff = 2-1-1 for legs I, II, and III, respectively. The palpal setal formula fPp = 0-B-B-BBB2-6Bcof is used to summarize the chaetotaxy of the palps. The chaetotaxy of the trochanter, femur, and genu is represented by the

first three elements, respectively. The setae can be nude (N), barbed (B), or absent (0). The palpal tibia (fourth element in the formula) has three barbed setae (BBB) and a two-pronged palpal tibial claw (2). The palpal tarsus (the last element) has six barbed setae (6B), one solenidia (o>), and one eupathid (f). All measurements are in micrometers. Length of the idiosoma was measured from the anterior tip of the prodorsal sclerite to the posterior end of the idiosoma. Leg lengths were measured from the basal end of the trochanter (Tr) to the base of the pretarsal claws. The IP is the sum of the leg lengths. Lasioerythraeus Welbourn & Young, n. gen. Type-species: Lasioerythraeus johnstoni Welbourn & Young, n. sp. Larval Lasioerythraeus. fnTr = 1-1-1; fnBF = 4-4-3; fnTF (telofemur) = 5-5-5; fnGe = 8-8-8; fnTi = 15-15-15; fSol = 1(0-1-2-1), 11(0-0-2-1), 111(00-1-0); fk = 1(1-1), 11(1-0), 111(0-0); fr= 2-2-1; fPp = 0-B-B-BBB2-6Botf; paired claws on all legs with numerous branching setules, but without distal hook; empodium on all legs clawlike; dorsal eupathid (fh) on tarsus legs I and II each with a companion seta (z); 0 tibia leg I without companion seta; all barbed setae on legs setiform; eyes 2/2; palpal tibial claw with 2 tines and may also have 3-5 basal setules. Postlarval Lasioerythraeus (DN and Adult). Measurements are given as range for the adults with range of DN in parentheses. Idiosoma 1,0901,743 (692-1,133) (im long, 867-1,162 (521-982) nm wide; prodorsal sclerite well developed between the prodorsal trichobothria; anterior end of prodorsal sclerite with 7-10 long setae (3-4 in DN) and a pair of trichobothria; between the anterior and posterior trichobothria are 2 pairs of long truncate setae (LI and L2), 1-3 pairs of interme-

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diate-length setae near the posterior pair of trichobothria, and 16-24 scattered short, acute setae (DN with 2 pairs of long truncate setae and 1-2 pairs of shorter setae); 1 pair of eyes on each side of the prodorsal sclerite, each pair set on an ocular sclerite with pair of long truncate setae; dorsal idiosomal setae of 2 distinct types, scattered long and truncate and the more numerous short and acute setae. One supracoxal seta above coxal field leg I and 2 supracoxal setae on anteriodorsal surface of coxal field leg II. Genital valves with a total of 50-60 setae in female, male with 20-24 setae and 2-3 in DN; anal valves with 12-20 setae in adults and 12 in DN. Gnathosoma: chelicerae styletlike and retractable. Anterior end of gnathosoma with fringe and 8-16 ventral and lateral setae. Palp with 5 segments (Tr, Fe, Ge, Ti, and Ta). Palpal trochanter with 8-12 barbed setae (3-6 in DN). Palpal genu with 26-38 barbed setae (9-12 in DN), approximately midway along dorsal surface a single very long seta 104-125 Mm (71-87 /an in DN); palpal tibia with 9-13 setae (7-11 in DN) and 3 ventral conelike spines (2 in DN), spines sometimes with small serrations; palpal tarsus with 5-12 o> and 11-17 eupathidia (5-7 in DN) and 46 branched setae (2 in DN). Legs: femora on all legs divided (basifemur and telofemur). All legs with 2 types of normal setae; 1 type short and nude or with few barbs, and the other type long with numerous short barbs. Short setae are more numerous with long setae widely scattered but usually more numerous at the distal end of leg segments. Setae on ventral side of tarsus on all legs with numerous barbs. Trochanter, basifemur, and telofemur on all legs without solenidia. Microseta k present on distal end of genu legs I, II, and tibia leg I. Leg I 2,267-2,618 (1,532-1,568 DN) Mm; leg II 1,501-1,908 (1,050-1,123 DN) Mm; leg III 1,6992,169 (1,252-1,346 DN) urn- leg IV 2,534-3,161 (1,949-2,006 DN) Mm. Distribution. The three species discussed in this paper were found in Mississippi, Texas, and Arkansas. In addition, several unnamed taxa were found in collections of larval and postlarval Erythraeinae from six states (Arizona, Florida, Idaho, Iowa, Maryland, and Nebraska), Brazil, Mexico, and Haiti, indicating a widespread distribution of the genus in North and South America. Lasioerythraeus johnstoni Welbourn & Young, n. sp. Holotype larva from MISSISSIPPI, Washington Co., ex lst-instar nymphal Lygus lineolaris (Hemiptera: Miridae), 30-VIII-1984, AL-3205. Eighteen larval paratypes collected in 1984 from MISSISSIPPI, Washington Co.: 1 from a lst-instar L. lineolaris, AL-3205; 3 (1 each) from 3 lst-instar nymphal Holcostethus sp. (Hemiptera: Pentatomidae), AL-3206; 1 from a 1st- or 2nd-instar nymphal Holcostethus sp., AL-3201; 1 from an adult whitefly (Homoptera: Aleyrodidae), AL-3204; 12 (1

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each) from 12 nymphal Cicadellidae (Homoptera), AL-3208. Seven reared postlarval paratypes from MISSISSIPPI, Washington Co., AL-3209: 1 female reared from larva attached to nymphal L. lineolaris; 1 male reared from larva attached to nymphal L. lineolaris; 4 DN (1 each) reared from larva attached to nymphal L. lineolaris; 1 DN reared from larva attached to nymphal cicadellid. Larva. Measurements are of holotype with range of larval paratypes in parentheses. Idiosoma (Fig. 1 A and F). Engorged 580 (470-642) Mm long, 323 (265-415) Mm wide; 1 pair of eyes set in an ocular sclerite on each side of prodorsum, anterior eye 19 (15-22) Mm, posterior eye 17 (14-18) Mm, distance between eyes 10 (11-17) Mm. Dorsum hypertrichous with 44 (43-45) idiosomal setae (includes setae posterior to ih cupule); dorsal setae long, 5365 Mm anteriorly and 61-66 Mm posteriorly, with setules (Fig. ID); cupules ia, im, ip, and ih present; supracoxal seta (el) 4. One pair (la) of barbed intercoxal setae between coxal field leg I, 52 fim, and 1 pair (3a) between coxal field leg III, 60 Mm; seta lb on coxal field leg I, 79 Mm; coxal field of legs II and HI each with 1 seta (2b and 3b), 46 and 49 Mm, respectively; 4 pairs of setae anterior to ih cupule. Prodorsal sclerite (Fig. IB): with numerous small punctations over entire surface, without striations, anterior margin concave with lateral shoulders, widest at level of PL setae; AM setae trichobothrial, second pair of trichobothria (S) near posterior margin; AL > S > PL > AM; both pairs of prodorsal trichobothria flagellate, with setules. Standard measurements of the prodorsal sclerite of holotype with mean, range of 18 larval paratypes in parentheses: AM 63 (61, 54-65) Mm; AA 14 (13, 11-16) Mm; AW 67 (65, 60-68) Mm; AL 87 (84, 76-90) Mm; PW 95 (88, 81-95) Mm; PL 67 (67, 60-73) Mm; AP 41 (36, 33-41) Mm; SB 20 (16, 14-19) Mm; S 76 (75, 67-84) Mm; PSB 6 (7, 6-8) Mm; ASB 99 (93, 88-99) Mm; SD 105 (99, 94-105) Mm; ISD 77 (75, 71-80) nm; W 139 (131, 118-139) Mm; PW/SD 0.92 (0.89, 0.81-0.94). Gnathosoma (Fig. 1 A, C, E, and F): palpal setal formula fPp = 0-B-B-BBB2-6Batf; palpal tibial claw 2 pronged with 2-5 small setules (not always visible); palpal tarsus with a> and one eupathid; 2 pairs of nude adoral setae (or), distal pair (orl) 24 Mm, proximal pair (or2) 6 Mm; subcapitular setae (scl) barbed, 35 Mm; palpal supracoxal seta (e) 5 Mm; cheliceral blade small (15 Mm long, 12 Mm wide), curved with a single tooth. Distal end of subcapitulum with fringe. Legs (Fig. 2): all legs with seven segments (Tr, BF, TF, Ge, Ti, Ta, Pt) beyond the coxal field; pretarsus (Pt) legs I—III with clawlike empodium; paired claws with numerous branching setules, but without terminal hook (Fig. 2G). Measurements of the holotype with mean, range, and number of larval paratypes measured in parentheses. Positions of specialized setae are given as a ratio of the segment length from the proximal end of the segment. All specialized setae are on the dorsal surface of the segment unless otherwise noted. IP 2,106

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Fig. 1. Larval L. johnstoni n. gen. and sp. (A) Dorsal idiosoma. (B) Prodorsal sclerite. (C) Palpal tibia and tarsus (ventral view). (D) Dorsal idiosomal setae. (E) Palpal trochanter, femur, genu, and tibia. (F) Ventral idiosoma. Adoral setae, orl and or2; subcapitular setae, scl; supracoxal setae, e and el; cupules, ia, im, ip, and ih; anteromedial setae, AM; anterolateral setae, AL; posterolateral setae, PL; eupathid, f; solenidion, w; intercoxal setae, ia and 3a; coxal field setae, lb, 2a, and 3b. Scale bars = 100 ^m (A, B, E, and F) and 50 ^m (C and D). Mm (2,069 Mm, 1,934-2,187 Mm, 18). Leg I (Fig. 2 A and D) 683 Mm (677 Mm, 631-715 Mm, 18); coxal field with 1 branched seta (IB); trochanter IB; basifemur 4B; telofemur 5B; genu 8B, a 34 Mm (30 Mm, 27-36 Mm, 18) at 0.62 (0.57, 0.55-0.59, 18); microseta (k) 10 Mm (12 Mm, 10-15 Mm, 18) at 0.93

(0.92, 0.88-0.94, 18); tibia 15B, 2 28 Mm (26 Mm, 18-30 Mm, 18) and 23 Mm (24 Mm, 20-27 Mm, 18) at 0.81 (0.81, 0.78-0.82, 18) and 0.90 (0.90, 0.870.92, 18), respectively; microseta (k) 10 Mm (11 Mm, 9-13 Mm, 16) at 0.95 (0.94, 0.91-0.96, 17); tarsus 26B, a> 20 Mm (19 Mm, 17-21 Mm, 16) at 0.46

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Fig. 2. Larval L. johnstoni n. gen. and sp. (A) Leg I (trochanter-tibia). (B) Leg II (trochanter-tibia). (C) Leg III (trochanter-tibia). (D) Tarsus leg I. (E) Tarsus leg II. (F) Tarsus leg III. (G) Pretarsal claws and empodium. Solenidia, a, (f>, and o>; famulus, e; microseta, k; dorsal eupathid, fh; ventral eupathid, fp; companion seta to dorsal eupathid, z. Scale bars = 100 Mm (A-F) and 50 ^m (G).

(0.45, 0.39-0.47, 17) famulus (c) 4 fim (4 nm, 2-5 16) at 0.44 (0.44, 0.40-0.50, 16), e at 0.42 (0.42, Mm, 11) at 0.55 (0.52, 0.48-0.55, 14), dorsal eu- 0.38-0.50, 11), fh 29 Mm (28 Mm, 24-32 Mm, 17) pathid (fh) 28 Mm (27 /on, 20-30 Mm, 18) at 0.84 at 0.86 (0.83, 0.79-0.90, 18) with companion seta (0.85, 0.82-0.91) with a companion seta (z) (7 Mm) (6 Mm) and an associated nude (or nearly nude) and an associated nude seta (18 Mm), subterminal normal seta, fp 17 Mm (17 Mm, 14-19 Mm, 16) at eupathid (fp) 19 Mm (18 Mm, 15-21 Mm, 15) at 0.90 0.90 (0.88, 0.85-0.92, 16). Leg III (Fig. 2 C and (0.89, 0.83-0.91, 16). Leg II (Fig. 2 B and E): 605 F): 819 Mm (799 Mm, 749-848 Mm, 18); coxal field Mm (593 Mm, 554-632 Mm, 18); coxal field IB; tro- IB; trochanter IB; basifemur 3B; telofemur 5B; chanter IB; basifemur 4B; telofemur 5B; genu 8B, genu 8B; tibia 15B, with 1 0 27 Mm (22 Mm, 20k 11 Mm (10 Mm, 9-12 Mm, 18) at 0.91 (0.90, 0.83- 27 Mm, 18) at 0.05 (0.05, 0.04-0.07, 18); tarsus 22B, 0.94, 18); tibia 15B, 2 23 nm (22 Mm, 17-25 Mm, fp 14 Mm (16 Mm, 14-18 Mm, 17) at 0.91 (0.91, 18) and 15 Mm (12 Mm, 10-15 Mm, 17) at 0.12 (0.11, 0.89-0.92, 17). 0.10-0.14, 18) and 0.86 (0.85, 0.83-0.88, 18), reDeutonymph. Measurements are the mean of 5 spectively; tarsus 23B, co 17 Mm (14 Mm, 12-18 Mm, reared deutonymphs (paratypes) with range in pa-

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I Fig. 3. Deutonymphal L. johnstoni n. gen. and sp. (A) Dorsal idiosoma. (B) Prodorsal sclerite. (C) Eyes. (D) Dorsal idiosomal setae. (E) Palp. Cupules, ia, im, and ip. Scale bars = 200 Mm (A), 100 fim (B and E), and 50 fim (C and D). Fig. 4. Adult L. johnstoni n. gen. and sp. (A) Prodorsal sclerite (female). (B) Ventral palpal tibia and tarsus (female). (C) Dorsal palpal tibia and tarsus (female). (D) Dorsal setae (female). (E) Leg I of female (excluding trochanter). (F) Leg II of female (excluding trochanter). (G) Leg III of female (excluding trochanter). (H) Leg IV of female (excluding trochanter). (I) Prodorsal sclerite (male). Scale bars = 100 fim (A-C and I), 50 (im (D), and 500 nm (E-H).

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rentheses. Idiosoma ovoid 717 (692-752) Mm long by 560 (521-621) Mm wide (Fig. 3A). One pair of eyes set on an ocular sclerite 77 (71-85) nm long and 55 (51-58) nm wide with 1 pair of long truncate setae 77-87 (71-94) ^m (Fig. 3C). Dorsal setae of 2 distinct types (Fig. 3D): long, thick, and truncate 74-96 (55-108) fim, and short and acute 35-43 (30-49) jam; majority of setae short. Anal valve with 6 pairs of setae. Genital valve with 1 pair of setae (occasionally with an extra unpaired seta). Gnathosoma: anterior end of gnathosoma with fringe and 8-10 ventral and lateral setae. Palpal trochanter with 3-6 setae, palpal femur with 19-28 setae; palpal genu with 9-12 setae, 1 dorsal seta very long 81 (71-87) Mm; palpal tibia with 6 barbed setae and 2 ventrally projecting conelike spines; palpal tibial claw entire; palpal tarsus with 2 branched setae, 7-8 co, 10 eupathidia (Fig. 3E). Prodorsal sclerite (Fig. 3B): 293 (271-306) urn long by 80-87 (74-98) nm wide; anterior end with 4 (occasionally 3) long setae 152 (128-174) nm and a pair of filiform trichobothria 115 (107-128) nm; posterior end of prodorsal sclerite with a second pair of filiform trichobothria 140 (138-151) /un; crista metopica connecting the 2 pairs of trichobothria and extending slightly posterior to the posterior pair; 2 pairs of long truncate setae (LI, L2) 115 (108-124) urn and 2-3 short setae 62 (56-66) Mm between the trichobothria. ISD 230 (207-254) Mm. Legs: all legs with 2 types of normal setae, 1 type short (37-70 Mm) and nude or with few setules, and the other type long (56-125 Mm) with numerous short barbs. IP 5,783 Mm- Leg I 1,532 (1,523-1,548) Mm; leg II 1,050 (963-1,090) Mm; leg III 1,252 (1,143-1,293) Mm; leg IV 1,949 (1,7682,022) Mm. Genu: leg I with 1 a in middorsal area, leg II-IV each with 1 basal a (occasionally absent). Tibia: leg I with 18-22 (f> distributed along dorsal surface with majority on distal half, leg II with 56 4> on basal half of segment, leg III and IV with 2-3 basal 0. Tarsus: leg I with 26-33 to and famulus on dorsal surface, leg II with 4 co and famulus, leg III with 2 co, leg IV without co. Adult Female. Measurements are of a single reared female paratype. Idiosoma ovoid, 1,272 Mm long by 995 Mm wide. One pair of eyes set on an ocular sclerite (100 Mm long by 69 Mm wide), with a pair of long truncate setae 120 Mm- Dorsal setae of 2 distinct types (Fig. 4D): long, thick, and truncate 87-101 Mm, and short and pointed 38-45 Mm; majority of setae short. Anal valves with a total of 20 setae. Genital valves with 51 setae. Prodorsal sclerite (Fig. 4A): 486 Mm long by 115-118 Mm wide; anterior end with 7 long setae; 2 pairs 152 Mm, 1 pair 210 Mm, 1 median seta 220 Mm, and a pair of filiform trichobothria 150 Mm; posterior end of prodorsal sclerite with another pair of filiform trichobothria 169 Mm; between the 2 pairs of trichobothria are 2 pairs of long truncate setae (LI, L2) 147-160 Mm, 3 pairs of medium-length setae (84 Mm) and 16 short setae (52-64 Mm). Gnathosoma: anterior end of gnathosoma with fringe and 12

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ventral and lateral setae. Palpal trochanter with 8-12 setae; palpal femur with 46-55 setae; palpal genu with 26 setae, 1 dorsal seta very long, 111 Mm; palpal tibia with 11 setae and 3 ventrally projecting conelike spines; palpal tibial claw entire; palpal tarsus with 6 branched setae, 10 co, 11 eupathidia (Fig. 4 E and F). Legs (Fig. 4 E-H): all legs with 2 types of normal setae, 1 type short (3772 Mm) and nude or with few setules, and the other long (58-142 Mm) with numerous short barbs. IP 8,831 Mm. Leg I 2,356 Mm; leg II 1,660 Mm; leg HI 1,963 Mm; leg IV 2,852 Mm. Genu: leg I with 2 a in middorsal region, leg II with 1-2 basal . Tarsus: leg I with 58 co on dorsal surface, leg II with 8 co, leg III with 3-4 co, leg IV with 1 co. Distribution of Types. The holotype, 3 larval paratypes, paratype male, paratype female, and 2 paratype DN to be deposited in the National Museum of Natural History, Washington, D.C.; 2 larval paratypes and 1 paratype DN in the Field Museum of Natural History, Chicago; 2 larval paratypes and 1 paratype DN in the Canadian National Collection, Ottawa; 2 larval paratypes and 1 paratype DN in the British Museum (Natural History), London; 2 larval paratypes in the Mu-


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Table 2. Comparison of chaetotaxy of postlarval instars of two species of Lasioerythraeus L. johnstoni DN Prodorsal sclerite" No. setae at anterior end No. medium setae Palpal femur (n)

4 0

19-20

Vol. 80, no. 2 n. gen.

L. whitcombi

M

F 7 6

8-9 4 43

46-55

DN 3 0

M

F

6(7)

5-9

2

2

22

68-69

54-82

13-15 10-12 11-14

10 17

Palpal tibiafc 8

14

14

9

Palpal tarsus

7-8 6

5 15

10 11

7-9 5

Tarsus leg I Anal valves

26-33 12-14

58

79

26-28

73

18-20

20-24

12

14

(n)

0 b

15-16

86-94 16-20

Excluding trichobothria. Including the large ventral spines (two in DN and three in adults).

seum National d'Histoire Naturelle, Paris; and 2 paratypes and 1 paratype DN in the South Australia Museum, Adelaide. The remaining larval paratypes and paratype DN will remain in the Acarology Laboratory Collection, The Ohio State University, Columbus. Etymology. The generic name was derived from the combination of lasios (Gr.), meaning hairy, and erythros (Gr.), meaning red (Brown 1956), based on the animal's hypertrichous idiosoma and color in life. The specific epithet honors Donald E. Johnston of the Acarology Laboratory, The Ohio State University, for his numerous contributions to acarology. Lasioerythraeus shirleyanneae (McDaniel & Bolen, 1981), n. comb. Bochartia shirleyanneae McDaniel & Bolen, 1981, Proc. Entomol. Soc. Wash. 83: 40-43. Type locality: Rob and Bessie Welder Wildlife Refuge, 10 miles N Sinton, San Patricio Co., TEXAS, USA; 2-II-1978 (B. McDaniel and Eric G. Bolen); known only from holotype deposited in National Museum of Natural History, Washington, D.C. Diagnosis. Larval Lasioerythraeus; prodorsal sclerite with larger and less numerous punctations than L. johnstoni; anterior edge of prodorsal sclerite not clear but appears to be linear. With striated cuticle between eyes. Holotype unengorged, 395 Mm long by 212 nm wide. Standard measurements of holotype as follows: AM 55 ^m, AA 12 yum, AW 58 Mm, AL 78 Mm, PW 84 (im, PL 65 urn, AP 36 Mm, SB 14 Mm, S 67 Mm, PSB 9 Mm, ASB 89 Mm, SD 98 Mm, ISD 73 Mm, W 115 Mm, PW/SD 0.86. Legs: due to the poor condition of the holotype, especially the legs, it was not possible to get accurate counts of setae on the tarsus or make all measurements. IP 1,903 Mm. Leg I 646 Mm; coxal field 2B, trochanter IB; basifemur 4B; telofemur 5B; genu 8B, a 21 Mm at 0.54, k 11 Mm at 0.92; tibia 15B, 2 0 22 Mm and 18 Mm at 0.80 and 0.87,

respectively, k not visible; tarsus ?B, u> 15 Mm at 0.45, e 4 Mm at 0.59, fh 23 Mm at 0.88 with companion seta and modified setae anterior, fp 16 Mm at 0.91. Leg II 549 Mm; coxal field IB; trochanter IB; basifemur 4B; telofemur 5B; genu 8B, k 9 Mm at 0.92; tibia 15B, 2 0 11 Mm and 9 Mm at 0.12 and 0.87, respectively; tarsus approximately 22B, a> 9 Mm at 0.46, e at 0.40, fh 23 Mm at 0.83 with companion seta and modified seta anteriorly, fp 15 Mm at 0.90. Leg III 708 Mm; coxal field IB; trochanter IB; basifemur 3B; telofemur 5B; genu 8B; tibia 15B, 0 12 Mm at 0.06; tarsus approximately 20B, fp 14 Mm. Notes. McDaniel & Bolen (1981) stated that the paraxial claw on each leg possessed a "terminal ventrally directed hook. " In examining the holotype we failed to detect this structure. Lasioerythraeus whitcombi (Smiley, 1964), n. comb. Erythraeus whitcombi Smiley, 1964, Proc. Entomol. Soc. Wash. 66: 110; Smiley, 1966, Proc. Entomol. Soc. Wash. 68: 25-28. Type: holotype and 7 paratypes from cotton in Con way Co., ARKANSAS, 26-VII-1963 (W. H. Whitcomb). Examination and remounting of the type series showed the holotype and 3 paratypes to be adult females, 3 paratypes to be adult males, and 1 paratype a DN. Diagnosis. Postlarval Lasioerythraeus. Measurements are the range of the adults in the type series with differences in the DN noted. Idiosoma ovoid 1,352-1,429 Mm long by 927-1,260 Mm wide (DN 1,133 by 982 Mm). Dorsal setae of 2 types: long and thick (50-111 Mm) and short and pointed (30-51 Mm); majority of setae short. Anal valves with a total of 16-20 setae in females, 14 setae in males, and 12 in the DN. Genital valves with a total of 58-60 in the females, 73-81 setae on outer edge and a row of 21-22 in inner edge of males, and 2 in the DN. Prodorsal sclerite 405-578 Mm

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long by 108-134 pm wide; anterior end with 6-8 and only five co on the palpal tarsus. In addition, long setae 116-230 ^rn (DN with 3 long setae 146- the male L. johnstoni has four medium-length se158 nm) and a pair of filiform trichobothria 142- tae between the L2 setae and the posterior trich151 nm (109 /xm in DN); posterior end of prodorsal obothria, whereas L. whitcombi has only two such sclerite with another pair of filiform trichobothria setae. 161-188 Mm (181 urn in DN); between the trichThe females of both species are more difficult obothria on the sclerotized area are 2 pairs of long to separate, with L. johnstoni usually possessing setae 140-172 /xm (123-134 urn in DN), 15-24 fewer setae on palpal femur, fewer a; on tarsus leg short setae 34-68 iim (absent in DN) and a pair of I, and more setae on the anal valves. The only medium-length setae 71-106 /xm (61-66 /xm in character that appears to be consistent in distinDN). ISD 355-464 /*m (225 /xm in DN). Gnatho- guishing the females of both species is the number soma: anterior end of gnathosoma with fringe and of medium-length setae between the L2 setae and 10-18 ventral and lateral setae. Palpal femur with the posterior trichobothria, with three pairs on L. 62-82 setae; palpal genu with 25-37 setae, 1 dorsal johnstoni and only one pair on L. whitcombi. seta midway, long genu very long (104-125 Mm); The relationship of Lasioerythraeus to other palpal tibia with 10-13 setae and 3 ventral cone- North American Erythraeinae will remain uncerlike spines (2 in DN); palpal tibial claw entire tain until the other three genera (Erythraxus, Auwithout teeth; palpal tarsus with 4-6 branched se- gustsonella, and Tepozatlana), for which only tae, 10-12 w, 11-17 eupathidia. Legs: all legs with postlarval instars are known, are reared. Beron 2 types of normal setae, 1 type short (29-79 Mm) (1982) suggested Bochartia Oudemans was a synand nude or with few setules and the other long onym of Erythraeus based on his work in Bulgaria. (50-136 Mm) with numerous short barbs. IP 8,156- Welbourn (unpublished data) confirmed this syn9,856 Mm. Leg I 2,207-2,618 Mm; leg II 1,540- onymy based on rearings from Europe and the 1,908 Mm; leg III 1,796-2,169 Mm; leg IV 2,613- United States. Comparison of larval characters of 3,161 Mm. Genu: leg I with 1-2 a in middorsal; II, Lasioerythraeus with those of Erythraeus and III, and IV each with 2-3 (occasionally 4) basal a Paraphanolophus indicated that Lasioerythraeus (DN with single basal a on all legs). Tibia: leg I shared three characters with Paraphanolophus not with 55-75 0 (23-26 in DN) distributed along dor- found on Erythraeus: four normal setae on basisal surface with most on distal half, leg II with 11- femur legs I and II, absence of companion setae 15 (5-6 in DN) on basal half of segment, leg III with 0 on tibia leg I, and absence of distal hook and IV with 8-10 basal (3 in DN). Tarsus: leg I on pretarsal claws. with 73-94 a> (26-28 in DN) and famulus on dorsal The following key to the Erythraeidae of North surface, leg II with 9-11 OJ (5 in DN) and famulus, America is based on genera from Canada, the leg III with 6-7 w (2 in DN), leg IV with 2-3 a> United States, and Mexico. Four genera, Caeculi(none in DN). soma Berlese, Erythraxus, Augustsonella, and Tepozatlana, are known only from the postlarval instars and one genus, Hauptmannia Oudemans, is known only from the larval instar. Although it is Discussion likely that additional North American genera reLarval L. johnstoni differs from L. shirleyan- main to be discovered, this key considers all the neae in the presence of an ocular sclerite sur- common genera and should aid in the recognition rounding the eyes, distal # leg II nearly twice as of new genera. / leg III nearly twice as long, a leg I onelong, Because of their small size (especially larvae), third longer, and a wider prodorsal sclerite with specimens should be mounted, dorsal side up, on numerous small punctations. In addition, AM, AL, microscope slides for use with this key (see Krantz and S are usually longer in L. johnstoni, with mea- [1978] for details on mounting media, clearing surements of L. shirleyanneae only in the lower agents, and mounting techniques). To see the important postlarval characters on the palps and prorange for L. johnstoni. The postlarval stages of L. johnstoni and L. dorsal sclerite clearly, it is necessary to remove the tvhitcombi are very similar and can be difficult to gnathosoma and separate one palp from the distinguish. Table 2 summarizes the important dif- gnathosoma. The gnathosoma can be easily references between the postlarval stages of both moved from cleared specimens by first placing the species. The DN of L. johnstoni can be distin- mite ventral side up in a drop of mounting meguished from L. whitcombi by the presence of two dium. Using a pair of very fine dissecting needles, pairs of setae (excluding trichobothria) at the an- one needle is used to hold the mite and the other terior end of the prodorsal sclerite, whereas L. is inserted at the base of the gnathosoma and pulled whitcombi has only one pair and a median seta. away from the idiosoma. Using a similar proceMale L. johnstoni can be distinguished from the dure, one palp can be separated from the gnathomale L. whitcombi by the eight to nine setae at soma. After dissection the mite should be turned the anterior end of the prodorsal sclerite (exclud- dorsal side up, gnathosoma and loose palp aring trichobothria), fewer setae on the palpa femur, ranged near the idiosoma, and a cover slip applied.

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Fig. 5. (A) Erythraeus sp. (larva) pretarsal claws and empodium. (B) Erythraeus sp. (larva) tibia leg I. (C) Paraphanolophus metcalfei Smiley, 1968 setae on leg I. (D) Erythraeus sp. (adult) palpal tibia and tarsus (dorsal). (E) Palpal tibial claw of Balaustium sp. (F) Dorsal view of Balaustium sp. (adult); A, eye; B, urnula. Solenidion, ; microseta, k; ventral eupathid, fp; companion seta to , ad. Scale bars = 50 Mm (A-F).

Key to the Genera of North American Erythraeidae 1. 2(1). 3(2).

4(3).

Deutonymph or adult 10 Larva 2 Two eyes on each side of prodorsum (Fig. 1A) Subfamily Erythraeinae . . . 3 One eye on each side of prodorsum . . . 5 Basifemur legs I and II each with 4 setae (Fig. 2 A and B); pretarsal claws on legs I—III without distinct distal clawlike hook (Fig. 2G); on tibia leg I without companion seta (Fig. 2A) .. 4 Basifemur legs I and II each with 3 (occasionally 2) setae; 1 pretarsal claw on 5(2). legs I—III with distinct distal clawlike hook (Fig. 5A); distal $ on tibia leg I with companion seta (ad) (Fig. 5B); hosts: Homoptera Erythraeus Latreille, 1806 Dorsal idiosoma neotrichous (>80 setae); distance between AL and PL setal bases (AP) less than the distance 6(5). between base of AL setae and anterior edge of prodorsal sclerite; palpal tib-

ial claw entire or bifurcate, without barbs on inner surface; usually with some setae on legs with large flat dorsal setules (Fig. 5C); hosts: Homoptera Paraphanolophus Smiley, 1968 Idiosoma with