Key and checklist of the bristletails (Microcoryphia)
Transcription
Key and checklist of the bristletails (Microcoryphia)
Key and checklist of the bristletails (Microcoryphia) of America north of Mexico Mahew L. Bowser May 9, 2012 1 Apology Below is a dra checklist of and key to the jumping bristletails (Microcoryphia or Archaeognatha) of America north of Mexico based primarily on existing keys (Wygodzinsky and Schmidt, 1980; Sturm, 1983; Ferguson, 1990; Mendes, 1990; Sturm, 1991) and descriptions (Silvestri, 1911; Allen, 1995; Sturm, 2001; Packauskas and Shofner, 2010). I apologize for the paucity of figures and the sometimes ambiguous characters used. I first constructed this key for my own use, but future dras should be increasingly accessible. Please contact me at [email protected] if you have questions or if you find problems with the key. e institutions below are referred to in the text. CAS California Academy of Sciences, San Francisco, California IEA Instituto di Entomologia Agraria, Portici/Napoli, Italy (Is this now DEZA?) KNWR Kenai National Wildlife Refuge, Soldotna, Alaska PAS Polish Academy of Sciences, Kracov, Poland UAM University of Alaska Museum of the North, Fairbanks, Alaska USNM U.S. National Museum of Natural History, Washington D.C. UWBM Burke Museum of Natural History and Culture, Seale, Washington 2 Chelist Family Mailidae Subfamily Mailinae Genus Mesomailis Subgenus Mesomailis 1 Mesomailis leei Sturm, 1991 Distribution: USA: California (Sturm, 1991). Type Material: holotype ♂, allotype ♀ and paratype ♂ and ♀ at CAS (Sturm, 1991). Mesomailis nearctica Silvestri, 1911 Mixomailis remingtoni Paclt, 1972 Distribution: USA: Arizona (Mendes, 1992; Sturm, 1991), California (Silvestri, 1911; Sturm, 1991; Baldo et al., 2010), Colorado (Silvestri, 1911), Nevada (Sturm, 1991; Baldo et al., 2010), and Utah (Baldoetal2010, KNWR:Ento:8123). Type Material: Type ♀ and paratype ♂ and ♀ at IEA (Sturm, 1991). Mesomailis cf. nearctica sensu Baldo et al. (2010) Distribution: USA: California, Nevada, and Utah (Baldo et al., 2010). Mesomailis strenua (Silvestri, 1911) Mailis strenua Silvestri, 1911 Pedetontus strenuus Smith, 1970 Distribution: USA: California (Silvestri, 1911). Subgenus Raroilis Mesomailis californica Sturm, 1991 Distribution: USA: California (Sturm, 1991). Type Material: holotype ♂, allotype ♀, and paratype ♂ and ♀ at CAS (Sturm, 1991). Mesomailis canadensis Sturm, 1991 Distribution: CANADA: British Columbia (Sturm, 1991). USA: Oregon (KNWR:Ento:8159). Type Material: holotype ♂; allotype ♀; 9 ♂, 16 ♀, and 14 immature paratypes at USNM (Sturm, 1991). Genus Trigoniophthalmus Trigoniophthalmus alternatus (Silvestri, 1904) Mailis alternata Silvestri, 1904 Distribution: USA: New York (Silvestri, 1911; Wygodzinsky and Schmidt, 1980); Connecticut, Maryland, New Jersey, and Pennsylvania (Wygodzinsky and Schmidt, 1980). Subfamily Petrobiinae Genus Leptomailis Leptomailis californica Sturm, 1991 Distribution: USA: California (Sturm, 1991). Type Material: type ♂, allotype ♀, and a paratype ♂ at CAS (Sturm, 1991). Genus Meximailis 2 Meximailis cokendolpheri Kaplin, 1994 Distribution: USA: New Mexico (Kaplin, 1994). Genus Neomailis Neomailis halophila Silvestri, 1911 Neomailis halophilus Silvestri, 1911 Distribution: USA: California (Silvestri, 1911; Benedei, 1973; Mendes, 1992). Genus Pedetontoides Pedetontoides atlanticus Mendes, 1981 Distribution: USA: North Carolina (Mendes, 1981). Type Material: holotypes and paratypes at PAS except for two paratype ♀’s in the collection of Luís Mendes (Luís Mendes, personal communication). Pedetontoides cf. atlanticus Distribution: CANADA: British Columbia (KNWR:Ento:8191) Genus Pedetontus Subgenus Pedetontus Pedetontus californicus (Silvestri, 1911) Distribution: USA: California (Silvestri, 1911; Mendes, 1992; Sturm, 2001). Pedetontus saltator Wygodzinsky and Smidt, 1980 Distribution: USA: Connecticu, Massachuses, New Jersey, New York, and Pennsylvania (Wygodzinsky and Schmidt, 1980). Pedetontus superior (Silvestri, 1911) Distribution: USA: Oregon (Silvestri, 1911). Pedetontus sii Sturm, 2001 Distribution: USA: California (Sturm, 2001). Pedetontus yosemite Sturm, 2001 Distribution: USA: California (Sturm, 2001). Subgenus Verhoeffilis Pedetontus calcaratus (Silvestri, 1911) Distribution: CANADA: British Columbia (Sturm, 1991; KNWR:Ento:8151, KNWR:Ento:8161). USA: Colorado (Silvestri, 1911; Mendes, 1981). Pedetontus gershneri Allen, 1995 Distribution: USA: Arkansas (Allen, 1995). 3 Pedetontus persquamosus (Silvestri, 1911) Distribution: USA: California (Silvestri, 1911). Pedetontus submutans (Silvestri, 1911) Distribution: CANADA: British Columbia (KNWR:Ento:8158). USA: Alaska (UAM:Ento:87248), Oregon (Silvestri, 1911, KNWR:Ento:8197), and Washington (Silvestri, 1911). Genus Petridiobius Subgenus Petridiobius Petridiobius arcticus (Folsom, 1902) Mailis arctica Folsom, 1902 Distribution: CANADA: British Colulmbia (KNWR:Ento:8195) USA: Alaska (Folsom, 1902; Sturm and Bowser, 2004, KNWR:Ento:7292). Subgenus Pacltiobius Petridiobius canadensis Sturm, 2001 Distribution: CANADA: British Columbia (Sturm, 2001). Genus Petrobius Petrobius brevistylis Carpenter, 1913 Petrobius canadensis Paclt, 1969 Distribution: CANADA: New Brunswick and Nova Scotia (Wygodzinsky and Schmidt, 1980). USA: Maine, Massachuses, New Hampshire, and Rhode Island (Wygodzinsky and Schmidt, 1980) Family Meinertellidae Genus Hypomailoides Hypomailoides forthaysi Paauskas and Shofner, 2010 Distribution: Kansas (Packauskas and Shofner, 2010). Hypomailoides texanus Silvestri, 1911 Distribution: Texas (Silvestri, 1911). Genus Mailinus Mailinus aurantiacus Sött, 1897 Mailis aurantiacus Schö, 1897 Mailinus nevadensis Sweetman, 1937 Distribution: CANADA: British Columbia (Sturm and Bach de Roca, 1992; KNWR:Ento:8130). USA: California (Silvestri, 1911; Sturm and Bach de Roca, 1992); Colorado (Silvestri, 1911); Arizona, Nevada, and Utah (Sturm and Bach de Roca, 1992). 4 Genus Mailoides Mailoides banksi Silvestri, 1911 Distribution: USA: Arkansas (Allen, 1995), Maryland (Wygodzinsky and Schmidt, 1980), North Carolina (Mendes, 1981), and Virginia (Silvestri, 1911; Mendes, 1992). Mailoides petauristes Wygodzinsky and Smidt, 1980 Distribution: USA: New Jersey (Wygodzinsky and Schmidt, 1980) Genus Neomailellus Neomailellus sp. Distribution: USA: Georgia (Sturm, 1984; Wygodzinsky, 1967) and Florida (Wygodzinsky, 1967). 3 Key 1. All segments of antennae completely devoid of scales; median sclerites of urosternites reduced in size; each urosternite with not more than one pair of eversible vesicles (Figure 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Meinertellidae, 2 Scales present on at least basal antennal segments (Figure 2); median sclerites of urosternites well developed; urosternites II-V each with one or two pairs of eversible vesicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Machilidae, 7 5 Figure 1: Photo of the head of a Meinertellid bristletail, probably Mailoides banksi, Norfolk, Virginia, March 7, 2009. Photo by Sco Justis. 6 Figure 2: Macrophoto of the face of an unidentified bristletail (subfamily Petrobiinae) from Chimney Flat, Smith River National Recreation Area, Del Norte County, California on June 11, 2008. Photo by Joyce Gross. 2. Coxal styli absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Coxal styli present, at least on legs III . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Lateral ocelli elongate, extending medially in front of the compound eyes (Figure 3.A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neomailellus Lateral ocelli egg-shaped or elliptical, sublateral to the compound eyes (Figure 3.B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mailinus aurantiacus A B Figure 3: Compound eyes and lateral ocelli of Meinertellidae, aer Silvestri (1911). A. Neomailellus mexicanus. B. Mailinus aurantiacus. 4. Coxa of legs II and III with styli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mailoides, 6 Coxa of legs III only with styli . . . . . . . . . . . . . . . . . . . . . . . . . . Hypomailodes, 5 7 5. Labial palpi of males with a large capitate process, its apex covered with distinct spines occurring proximally on the anterior face of the second segment of the labial palpus, with only a few scaered, short spines near the base of the capitate process. Females with dark pigment markings on at least the coxa of legs I. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hypomailodes texanus Process of labial palpi of males much more triangular, lacking spines on its apex, with an oval cluster of longer spines on a raised mound near the base of the process. Females without dark pigment markings on coxae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hypomailodes forthaysi See Packauskas and Shofner (2010) for further diagnostic characters of H. forthaysi. 6. Clypeus predominantly light colored, with faint central longitudinal spot. Maxillary palp with segments III-V extensively darkened; second segment with one pigment spot; fourth segment of maxillary palp very short and stout, three times as long as wide. Coxa and femur of forelegs with very small pigment spots, tarsus of third pair of legs uniformly darkened; basal tarsal segment of legs I not darker than the others; anterior gonapophyses with approximately 45 divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mailoides petauristes Clypeus light colored along middle, broadly margined with dark pigment. Segments III-V of maxillary palps with dark pigment forming narrow, dark rings; second segment of palp with two spots; fourth segment of maxillary palp slender, about six times as long as wide. Coxa and femur of forelegs with large pigment spots; third pair of legs with first tarsal segment conspicuously darkened. Anterior gonapophyses with approximately 55 divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mailoides banksi 7. Scales present on antennal flagellum . . . . . . . . . . . . . . . . . . . . . . . . . Machilinae, 8 Antennal flagellum devoid of scales . . . . . . . . . . . . . . . . . . . . . . . . . Petrobiinae, 15 8. Lateral ocelli small, tear-dropped shaped, submedial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trigoniophthalmus alternatus Lateral ocelli sole-shaped, extending laterally close to or beyond the lateral margin of the compound eyes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mesomailis, 9 9. Coxal stylets on midleg present . . . . . . . . . . . . . . . . . . . . . subgenus Raroilis, 10 Coxal stylets on midleg absent . . . . . . . . . . . . . . . . . . . subgenus Mesomailis, 14 Males of Mesomailis strenua, known from Shasta Springs, California, are unknown. Females should key out with Mesomailis leei, but M. strenua has longer spines on the ovipositor. See Silvestri (1911) and Sturm (1991). 10. At least one pair of coxal stylets of males modified, paddle-shaped (Figures 4, 5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 All coxal stylets of males normal, acute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8 Figure 4: Coxal stylet of midleg of a Mesomailis ♂ specimen from Osoyoos, British Columbia (KNWR:Ento:8275). 11. Coxal stylet of hindleg of males normal, acute . . . . . . . . . . . Mesomailis sp. A Coxal stylet of hindleg of males modified, at least somewhat broadened apically 12 I have seen specimens I am here calling Mesomailis sp. A from Osoyoos, British Columbia (KNWR:Ento:8275). 12. Coxal stylet of midleg of males modified, broadened with darkly pigmented, taered edges distally. (Figure 5). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mesomailis sp. B Coxal stylet of midleg of males normal, acute . . . . . . . . . . . . Mesomailis sp. C I have seen a specimen keying here to Mesomailis sp. B from Hells Canyon National Recreation Area, Oregon (KNWR:Ento:8120). I have seen a specimen keying here to Mesomailis sp. C from Asotin County, Washington (UWBM) Figure 5: Sketch of coxal stylet III of a UWBM specimen from Captain John Rapids, Asotin County, Washington. 13. Sensory field on femora I of male centrally with fringed tubercles; gonapophyses IX of female with very long setae on the proximal half, some of which are distinctly longer than the width of the gonapophyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mesomailis canadensis 9 Sensory field on femora I of male without fringed tubercles; hairs on proximal half of gonapophyses IX at most as long as width of the gonapophyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mesomailis californica 14. Tips of coxal stylets III of male represented by a knob-like structure; parameres VIII absent; terminal spines of gonapophyses IX extremely small, not projecting beyond the distal end of the gonapophyses . . . . . . . Mesomailis nearctica Tips of coxal stylets III of male of normal structure; parameres VIII highly reduced with at most 3 divisions; terminal spines of gonapophyses IX very small, but projecting slightly beyond the distal end of the gonapophyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mesomailis leei An additional, undescribed species similar to M. nearctica was partially described and figured by Baldo et al. (2010). 15. 1 + 1 eversible vesicles only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2 + 2 eversible vesicles on at least some abdominal segments . . . . . . . . . . . . . 17 16. Lateral ocelli of typical size or somewhat smaller, transverse, narrow (Figure 6). Distal chains of the antennae with 8-10 subarticles . . . . Neomailis halophila Lateral ocelli large, triangular to oval. Distal chains of the antennae with no more than 8 subarticles. . . . . . . . . . . . . . . . . . . . . . . . . . . . Leptomailis californica See Sturm (1991) for a more thorough comparison of Neomailis and Leptomailis. Figure 6: Compound eyes and lateral ocelli of Neomailis halophila, aer Silvestri (1911). 17. Lateral ocelli transverse, subelliptical, pear-shaped, or slightly sole-shaped, attaining only the apex of the ante-ocular sublateral area (Figure 7); paramera restricted to the IXth segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Petridiobius Lateral ocelli sole-shaped, aaining the frontal ante-ocular area (Figure 10); paramera variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Petridiobius and its relationship with Pedetontus are troublesome at present. Most specimens will be keyed cleanly by these couplets because the lateral ocelli of Pedetontus species generally are longer and usually do extend into the pigmented frontal anteocular area while the lateral ocelli of Petridiobius are restricted to the ante-ocular sublateral area; however there are specimens which I think might be Pedetontus, subgenus Pedetontus that could key either way. Also, the current descriptions of Petridiobius are confusing. I am forming an opinion that all Petridiobius from coastal Alaska and British Columbia should be called Petridiobius arcticus and that Petridiobius canadensis may be a junior synonym of this species. I think that Paclt’s (1970) redescription of Petridiobius arcticus is misleading. All specimens of Petridiobius that I have seen from the Aleutians to southern British Columbia have had 2 + 2 eversible vesicles on abdominal segments II-VI. 10 Figure 7: Face of Petridiobius arcticus specimen from Sitka, Alaska (UAM:Ento:87253). 18. Paramera annulated, present on the VIIIth and IXth segments. Ovipositor without interlocking, spine-like setae, though terminal spine-like setae may be present. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Paramera annulated or entire, restricted to the IXth segment. Ovipositor usually without interlocking, spine-like setae, but such setae present in Pedetontus calcaratus (Figure 9.B-C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 19. Abdominal sternites wide, obtuse. Apical spine of the abdominal stylets short and stout. Foreleg of male modified. Female ovipositor apically with 2-4 stout, fossorial setae. Lateral ocelli widest laterally, without a constriction in their middles (as in Figure 6). . . . . . . . . . . . . . . . . . . . . . . . . Meximailis cokendolpheri Abdominal sternites smaller, acute. Apical spine of the abdominal stylets long and stout. Foreleg of male not modified. Female ovipositor lacking stout setae. Lateral ocelli widest medially, with a pronounced constriction in their middles making them sole-shaped (as in Figure 10.C). . . . . . . . . Pedetontoides atlanticus I have seen specimens that appear to be nearly identical to Pedetontoides atlanticus from British Columbia (e.g., KNWR:Ento:8191); however, the distal segments of the labial palpi of males of the British Columbia specimens are more conical than in the corresponding illustration of male palpi of P. atlanticus (Fig. 6 in Mendes, 1981) 20. Molar area of mandible undentated or with 1-2 inconspicuous teeth; paramera short and entire (unsegmented), the penis long and robust. Male genitalia partially exposed, not completely covered by the IXth coxitesPetrobius brevistylis Molar area of mandible with four well-developed teeth (sometimes wearing down with age); paramera clearly pseudosegmented, the penis typical; male genitalia completely covered by the IXth coxites . . . . . . . . . . . . . . Pedetontus, 21 21. 2 + 2 eversible vesicles on abdominal coxites II-VI . . . subgenus Pedetontus, 22 2 + 2 eversible vesicles on abdominal coxites II-V only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . subgenus Verhoeffilis, 26 22. Lateral ocelli close together (separated by 0.08 mm or less); extremely soleshaped (i.e., with a strong constriction in the middle) (Figure 8.C,D) . . . . . . . 23 Lateral ocelli separated by a greater distance; form variable (Figure 8.A,B) . 24 11 A B C D Figure 8: Compound eyes, lateral ocelli, and faces of Pedetontus (Pedetontus) species. A. Pedetontus californicus. B. Pedetontus superior. C. Pedetontus yosemite. D. Pedetontus sii. A. and B. aer Silvestri (1911). C. and D. reproduced from Sturm (2001), copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission. 23. Lateral ocelli nearly touching each other (separated by 0.01-0.02 mm) (Figure 8.D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pedetontus sii Lateral ocelli separated by a greater distance (Figure 8.C) . Pedetontus yosemite 24. Compound eyes with a relatively large length of contact (distinctly more than half the length of the eyes); last segment of labial palp elongate and narrowly subcylindrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Compound eyes with smaller area of contact (about half the length of the eyes); last segment of labial palp shorter and more conical . . . Pedetontus californicus 25. Ovipositor extending beyond terminal apices of spines of last abdominal styli by about 1 mm or more . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pedetontus superior Ovipositor just reaching or not reaching terminal apices of spines of last abdominal styli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pedetontus saltator Forms keying to P. superior or P. saltator are in need of revision. At the time of their descriptions, males were unknown. Wygodzinsky and Schmidt (1980) noted that the length of the ovipositor may change during development and so may not be a reliable character for separation of these species. 26. No strong spines on distal segments of maxillary palps; processus triangularis poorly developed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pedetontus gershneri Strong spines on distal segments of maxillary palpi; processus triangularis well developed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 27. Ovipositor with interlocking, stout, spine-like setae (Figure 9.B, C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pedetontus calcaratus Ovipositor lacking stout, spine-like setae (Figure 9.A) . . . . . . . . . . . . . . . . . . . . 28 12 A B C Figure 9: Ovipositors of Pedetontus (Verhoeffilis) species. A. Pedetontus submutans, aer Silvestri (1911). B. Pedetontus calcaratus, aer Silvestri (1911). C. Pedetontus calcaratus specimen from Penticton, British Columbia. (KNWR:Ento:8151) 28. Lateral ocelli extremely thin, weakly sole-shaped (i.e., weakly constricted in the middle) (Figure 10.B) . . . . . . . . . . . . . . . . . . . . . . . . . . Pedetontus persquamosus Lateral ocelli strongly sole-shaped (i.e., strongly constricted in the middle) (Figure 10.C, D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pedetontus submutans A B C D Figure 10: Compound eyes and lateral ocelli of Pedetontus (Verhoeffilis) species. A. Pedetontus calcaratus, aer Silvestri (1911). B. Pedetontus persquamosus, aer Silvestri (1911). C. Pedetontus submutans, aer Silvestri (1911). D. Pedetontus submutans specimen from Sitka, Alaska (UAM:Ento:87248 or UAM:Ento:96672). 13 4 Gallery A B Figure 11: Photographs of Petridiobius arcticus by Derek Sikes. A. Lucas Island, Skilak Lake, Kenai Peninsula, Alaska, on June 29, 2011. B. Sitka, Alaska on September 19, 2008. Some characteristics of the paern of scales appear to be at least mostly consistent within this species: a pair of small, distinct, pale spots on the mesonotum and an alternating paern of three black and two paler patches on the abdominal tergites, the paler areas on the abdomen resembling an hour glass. 14 5 Anowledgments Alan de eiroz provided comments that greatly improved this key. I thank Derek Sikes, Joyce Gross, and Sco Justis for allowing me to use their photographs. References Allen, R. T. 1995. Pedetontus gershneri, a new species of Machilidae from the interior highlands of North America (Insecta: Microcoryphia). Entomological News 106:195–198. Baldo, L., A. de eiroz, M. Hedin, C. Y. Hayashi, and J. Gatesy. 2010. Nuclearmitochondrial sequences as witnesses of past interbreeding and population diversity in the jumping bristletail Mesomailis. Molecular Biology and Evolution URL http://mbe.oxfordjournals.org/content/28/1/195.full. Benedei, R. 1973. Notes on the biology of Neomailis halophila on a California sandy beach. Pan-Pacific Entomologist 49:246–249. Carpenter, G. H. 1913. e Irish species of Petrobius. Irish Naturalist 22:228–233. Ferguson, L. M., 1990. Insecta: Microcoryphia and ysanura. Chapter 30, pages 935–949 in D. L. Dindal, editor. Soil Biology Guide. John Wiley & Sons, New York. Folsom, J. W. 1902. Papers from the Harriman Alaska Expedition. XVII. Apterygota. Proceedings of the Washington Academy of Sciences 4:87–116. Kaplin, V. G. 1994. On the taxonomy of the genus Meximailis (ysanura, Machilidae). Zoologischekii Zhurnal 73:119–123. Mendes, L. F. 1981. Notes et description de ysanoures du Nouveau Monde (Apterygota: Microcoryphia et Zygentoma). Nouvelle Revue de Entomologie 11:221–231. Mendes, L. F. 1990. An annotated list of generic and specific names of Machilidae (Microcoryphia, Insecta) with identification keys for the genera and geographic notes. Estudos, Ensayos e Documentos 155:1–127. Mendes, L. F. 1992. 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