Medon icarus Caterino, 2023

Caterino, Michael S., 2023, A New, Flightless Species of Medon (Coleoptera: Staphylinidae: Paederinae) from High Appalachia, with Intraspecific Phylogeographic Analysis and Description of its Associated Larva, The Coleopterists Bulletin 77 (4), pp. 507-523 : 511-519

Medon icarus Caterino , new species

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( Figs. 4–8 )

Type Specimens. Holotype male: “ USA: TN: Sevier Co., 35.6529°N, 83.4378°W, SmokyMts NP, 6467’, Mt LeConte , vi.25.2019 M.Caterino & M. Ferro, sifted conifer litter” / “Clemson ENT CUAC000079305 ” / “Caterino DNA voucher, Ext. MSC-3486, Morphosp.MLc.012”; deposited in USNM . Paratypes (38; USNM, CUAC, AMNH, CNCI, FMNH): USA: TN: Sevier Co., Great Smoky Mountains National Park, Mt. LeConte , 35.6538, −83.4373, 1,999 m, 25-Jun-2019 ( CUAC000176446 , CUAC000176447 , CUAC000176448 , CUAC-000176449, CUAC000176450 , CUAC000176451 , CUAC000176452 , CUAC000176453 , CUAC-000176454 , CUAC000176455 ); USA: TN: Sevier Co., Great Smoky Mountains National Park, Mt. LeConte , 35.6542, −83.4368, 2,006 m, 28-Sep-2021 ( CUAC000159987 ); USA: TN: Sevier Co., Great Smoky Mountains National Park, Mt. Kephart , 35.6311, −83.3895, 1,885 m, 4-Jun-2018 ( CUAC-000079123 ); USA: TN: Sevier Co., Great Smoky Mountains National Park, Mt. Kephart , 35.6311, −83.3893, 1,886 m, 14-Sep-2021 ( CUAC000156758 , CUAC000176435 , CUAC000176436 ); USA: TN: Sevier Co., Great Smoky Mountains National Park, Mt. Kephart , 35.631, −83.3895, 1,894 m, 14-Sep-2021 ( CUAC000156780 ); USA: TN: Sevier Co., Great Smoky Mountains National Park, Off Hwy 441 , 35.6237, −83.4163, 1,394 m, 12-Mar- 2020 ( CUAC000110840 ); USA: NC: Swain Co., Great Smoky Mountains National Park, Clingmans Dome , 35.5597, −83.4992, 1,909 m, 14-Sep-2021 ( CUAC000156742 ); USA: NC: Haywood Co., Great Smoky Mountains National Park, Big Cataloochee Mt. , 35.6686, −83.1749, 1,745 m, 14- Jul-2020 ( CUAC000137686 ); USA: NC: Haywood Co., Great Smoky Mountains National Park, Big Cataloochee Mt. , 35.6724, −83.1761, 1,868 m, 14- Jul-2020 ( CUAC000137730 ); USA: NC: Haywood Co., Great Smoky Mountains National Park, Big Cataloochee Mt. , 35.6722, −83.1756, 1,876 m, 5-Nov-2020 ( CUAC000135165 , CUAC000139637 ); USA: NC: Haywood Co., Great Smoky Mountains National Park, Big Cataloochee Mt. , 35.6727, −83.1762, 1,862 m, 5-Nov-2020 ( CUAC000176419 , CUAC000176420 , CUAC000176421 , CUAC-000176422 , CUAC000176423 ); USA: NC: Haywood Co., Great Smoky Mountains National Park, Balsam Mt. Tr. , 35.6425, −83.2007, 1,575 m, 5-Nov-2020 ( CUAC000139752 ); USA: NC: Haywood Co., Great Smoky Mountains National Park, Balsam Mt. Tr. , 35.6453, −83.2025, 1,550 m, 5-Nov-2020 ( CUAC000135195 ); USA: TN: Sevier Co., Great Smoky Mountains National Park, Alum Cave Trail , 35.6427, −83.4426, 1,581 m, 28-Sep- 2021 ( CUAC000160050 , CUAC000160051 , CUAC-000160052 ); USA: TN: Sevier Co., Great Smoky Mountains National Park, Alum Cave Trail , 35.6425, −83.4427, 1,584 m, 25-Jun-2019 ( CUAC-000176424 , CUAC000176425 , CUAC000176426 , CUAC000176427 , CUAC000176428 , CUAC-000176429 ) .

Relationships among southern populations are more complicated. One large clade comprises some individuals from the Great Smoky Mountains (Clingmans Dome), the Plott Balsams (Lyn Lowry, Waterrock Knob, and Browning Knob), the Great Balsams (Mount Hardy, Black Balsam Knob, and Richland Balsam), and Huckleberry Knob in the Unicoi Mountains , far to the southwest of the others. Another rather shallow clade includes populations from Tusquitee Bald and Copper Ridge Bald in the Central Nantahalas, as well as Brasstown Bald, GA, directly to the south. This is sister to another clade comprising only Great Smoky Mountains populations, including Mount Kephart, Mount LeConte, Big Cataloochee, and (again) Clingmans Dome, as well as a number of slightly lower-elevation localities near each of them.

Other Material. NC: Jackson Co., Blue Ridge Pkwy National Park , Richland Balsam Mt., 35.367 6, −82.9902, 1,950 m, 8-May-2018; NC: Jackson Co., Blue Ridge Pkwy National Park , Richland Balsam Mt., 35.362 7, −82.9885, 1,890 m, 11-Sep-2019; NC: Haywood Co., Pisgah NF, Black Balsam Knob, 35.325 8, −82.8777, 1,851 m, 8-May-2018; NC: Haywood Co., Pisgah NF, Black Balsam Knob, 35.328 9, −82.8745, 1,839 m, 20-Oct-2020; NC: Jackson Co., Blue Ridge Pkwy National Park , Browning Knob, 35.463, −83.131, 1,871 m, 22-Sep- 2020; NC: Graham Co., Nantahala NF, Huckleberry Knob, 35.324, −83.9939, 1,662 m, 4-May-2020; NC: Graham Co., Nantahala NF, Huckleberry Knob, 35.323 5, −83.994, 1,680 m, 13-Oct-2020; NC: Graham Co., Nantahala NF, Cherohala Skyway, 35.317 1, −83.9833, 1,433 m, 4-May-2020; NC: Jackson Co., Blue Ridge Pkwy National Park , Mt. Lyn Lowry, 35.464 5, −83.1131, 1,858 m, 15-Jun- 2021; NC: Jackson Co., Blue Ridge Pkwy National Park , Mt. Lyn Lowry, 35.464, −83.11, 1,891 m, 22- Sep-2020; NC: Haywood Co., Blue Ridge Pkwy National Park , Mt. Hardy, 35.302 7, −82.9278, 1,865 m, 14-Apr-2020; NC: Haywood Co., Blue Ridge Pkwy National Park , Mt. Hardy, 35.303 6, −82.9269, 1,857 m, 8-Sep-2020; NC: Transylvania Co., Blue Ridge Parkway NP, 35.304 2, −82.8885, 1,690 m, 4-Apr-2015; NC: Haywood Co., Blue Ridge Pkwy National Park , Mt. Hardy, 35.303 6, −82.9269, 1,857 m, 8-Sep-2020; NC: Haywood Co., Pisgah NF, Mt. Pisgah , 35.425 4, −82.7564, 1,726 m, 13-Sep-2022; NC: Jackson Co., Blue Ridge Pkwy National Park , Waterrock Knob, 35.464 1, −83.1379, 1,913 m, 29- May-2018; NC: Swain Co., Great Smoky Mountains National Park , Clingmans Dome, 35.561 3, −83.5006, 1,940 m, 4-Jun-2018; GA: Towns Co., Chattahoochee NF, Brasstown Bald, 34.876 3, −83.8107, 1,385 m, 2-Jul-2020; GA: Towns Co., Chattahoochee NF, Brasstown Bald, 34.878 2, −83.8108, 1,346 m, 17-Nov-2020; NC: Macon Co., Nantahala NF, Copper Ridge Bald, 35.235 7, −83.5602, 1,568 m, 9-Jul-2019; NC: Macon Co., Nantahala NF, Copper Ridge Bald, 35.237 6, −83.5594, 1,545 m, 15-Sep-2020; NC: Graham Co., Joyce Kilmer Forest , jct. Indian & Santeetlah Cks. , 35.345 01, −83.967, 855 m, 24-Jun-2015; NC: Graham Co., Joyce Kilmer Forest , jct. Indian & Santeetlah Cks. , 35.342 6, −83.966, 865 m, 24-Jun- 2015; NC: Clay Co., Nantahala NF, Tusquitee Bald , 35.141 5, −83.7273, 1,582 m, 6-Jul-2021; NC: Clay Co., Nantahala NF, Tusquitee Bald , 35.141 9, −83.7269, 1,606 m, 6-Jul-2021; NC: Clay Co., Nantahala NF, Tusquitee Bald , 35.141 9, −83.7178, 1,532 m, 1-Sep-2020; NC: Graham Co., Nantahala NF, Teyahalee Bald, 35.258 5, −83.7959, 1,597 m, 9-Jul-2019; NC: Macon, Nantahala NF, Jones Gap, 35.074 6, −83.2355, 1,042 m, 16-Jul-2015; NC: Caldwell Co., Grandfather Mountain State Park , Daniel Boone Scout Tr., 36.111, −81.7964, 1,558 m, 6-Oct-2020; NC: Mitchell Co., Pisgah NF, Grassy Ridge Bald, 36.100 2, −82.0822, 1,865 m, 15-Aug- 2018; NC: Mitchell Co., Pisgah NF, Grassy Ridge Bald, 36.103 8, −82.0809, 1,854 m, 8-Jun-2020; NC: Yancey Co., Pisgah NF, Big Bald, 35.989 3, −82.4903, 1,651 m, 5-Aug-2020; TN: Unicoi Co., Cherokee NF, Big Bald , 35.990 38, −82.49269, 1,606 m, 25-May-2021; NC: Yancey Co., Pisgah NF, Woody Ridge Tr., 35.844 8, −82.2377, 1,616 m, 15-Jun-2020; NC: Yancey Co., Pisgah NF, Woody Ridge Tr., 35.844, −82.2347, 1,550 m, 19-Oct-2021; NC: Yancey Co., Pisgah NF, Woody Ridge Tr., 35.845 6, −82.2321, 1,397 m, 19-Oct-2021; NC: Jackson Co., Balsam Mt. Preserve, 35.370 3, −83.1216, 1,369 m, 15-Jun-2015; NC: Jackson Co., Balsam Mt. Preserve, 35.369 9, −83.1216, 1,391 m, 7-Feb-2015; NC: Jackson Co., Balsam Mt. Preserve, 35.375 1, −83.0981, 1,671 m, 15-Jun-2015; NC: Jackson Co., Balsam Mt. Preserve, 35.387 9, −83.1005, 1,211 m, 16-Jun-2015; NC: Jackson Co., Balsam Mt. Preserve, 35.375 3, −83.0982, 1,671 m, 7-Feb-2015; NC: Jackson Co., Balsam Mt. Preserve, 35.391 6, −83.1091, 1,007 m, 20-Jun-2015; NC: Buncombe Co., Pisgah NF, Big Butt Trail, 35.801 7, −82.3401, 1,626 m, 26-Jul-2015; NC: Buncombe Co., Pisgah NF, Big Butt Trail, 35.804 2, −82.3449, 1,488 m, 26-Jul-2015; NC: Buncombe Co., Pisgah NF, Big Butt Trail, 35.785 3, −82.3458, 1,798 m, 26-Jul-2015; NC: Buncombe Co., Pisgah NF, Big Butt Trail, 35.792 6, −82.3435, 1,709 m, 19-Mar- 2016; NC: Buncombe Co., Pisgah NF, Craggy Dome, 35.706 1, −82.3666, 1,838 m, 13-Sep-2022; NC: Buncombe Co., Pisgah NF, Craggy Dome, 35.707 7, −82.3657, 1,761 m, 13-Sep-2022; NC: Yancey Co., Pisgah NF, Devils Gap, 36.037, −82.431, 1,036 m, 24-Jul-2015; NC: Yancey Co., Pisgah NF, Devils Gap, 36.044 2, −82.4279, 1,140 m, 24-Jul-2015.

Description. Total body length: 2.6–3.4 mm; HL 0.51–0.59 mm (avg. 0.55), HW 0.55–0.63 mm (avg. 0.58); PnL 0.53–0.61 mm (avg. 0.56); PnW 0.55– 0.59 mm (avg. 0.57); EL 0.41–0.51 mm (avg. 0.48); EW 0.57–0.61 mm (avg. 0.59); AL 1.47–2.25 mm (avg. 1.70); n = 4 ♂ + 4 ♀. Coloration ( Figs. 4A, B ): body darkly rufescent, setose on most surfaces, with longer setae projecting from sides of head, pronotum, and abdomen, particularly posteriorly; apical antennomeres and palpomeres slightly lighter. Head ( Fig. 4E ) subquadrate, widest to rear, sides weakly convex, posterior angles distinctly rounded, dorsum slightly flattened, more convex ventrally; neck slightly more than one-third maximum head width; gular sutures separated throughout, minimum width of gula just behind middle, approximately one-tenth maximum head width, widening anteriorly and posteriorly; head with conspicuous reticulate microsculpture throughout; dorsal setae of head mostly inclinate toward midline, laterally becoming proclinate, with larger macrosetae projecting near posterior corners and above mandible insertions; a few anteriorly projecting and two cruciate setae on epistoma. Eye small, occupying about one-fourth of lateral side of head, comprising about 30 ommatidia. Antenna rather short, scape shorter than antennomeres 2–4 combined, antennomeres 2–7 slightly longer than wide, gradually widening to penultimate 3 antennomeres being as wide as long, apical antennomeres longer, subacute, all antennomeres setose.

Epistoma transverse, elevated slightly above labrum; labrum ( Fig. 5B ) short, rounded at sides, thickened at middle, with abrupt but shallow median emargination, with distinct anterior teeth at each side of it, anterior margin otherwise weakly sinuous; mandibles ( Figs. 5A, C ) strong, each with fimbriate basal prostheca about one-third mandible length; left mandible with strong apical tooth and three median teeth; right mandible with strong apical tooth and four median teeth. Labium ( Fig. 5E ) with broadly hexagonal mentum, ligula broadened to bases of palpomeres, its inner surface (prementum, Fig. 5F ) with continuous, U-shaped comb of stiff setae, apical lobes of prementum extending to apex of basal labial palpomere; inner apex of ligula with apical brush of stout setae, and a pair of slightly longer, fleshy lateral lobes; labial palpomere II twice as long as basal palpomere, bearing long subapical seta on ventrolateral surface, terminal labial palpomere thin, about two-thirds as long as penultimate. Maxillary stipes ( Fig. 5D ) with one strong seta at outer basal corner, galea and lacinia simply brushlike, without distinct teeth; palpifer with three strong setae along outer margin; basal maxillary palpomere short, curved, palpomere II longer, widening to apex, palpomere III (penultimate) slightly longer than 2, swollen to about 1.5× width of palpomere II, apical palpomere thin, digitiform, just over one-fourth length of palpomere III.

Pronotum ( Fig. 4E ) about as long as wide, widening from rounded basal corners to front, maximum width near anterior margin; disc with distinct, continuous lateral (and hypomeral) margin, including along anterior, cervical margin; dorsal setae of disc inclinate toward middle, each set in a broad, shallow puncture, impunctate along a narrow median band; lateral margins with 5 prominent projecting setae; disc with densely reticulate microsculpture. Elytra ( Fig. 4A ) short, midline length about two-thirds combined width, densely setose, all setae posteriorly directed, disc lacking distinct microsculpture; flight wings absent. Abdominal sclerites densely and finely setose, faintly shining.

Protibia slender, with continuous comb of setae along inner margin, margin disrupted in basal half by antennal cleaner; male protarsomeres 1–4 short, widened, with dense, flattened setae beneath; meso- and metatarsi with basal tarsomere only slightly longer than tarsomeres 2–4, apical tarsomere about as long as tarsomeres 3 and 4 combined.

Male sternite VII ( Fig. 4C ) with a comb of ~8 short, thick palisade setae on each side of shallow median emargination, with sparse, irregular row of longer setae basad the emargination; male sternite VIII more deeply emarginate, with few stronger setae lining emargination; male tergite IX narrowly but deeply emarginate, apices on either side obliquely truncate; male sternite IX elongate, setose, weakly emarginate at apex; female ventrites unmodified. Aedeagus ( Fig. 6 ) with broad basal foramen, sinuously parallel-sided to near the apex, ventral plate flat, widening to subtruncate apex, apical corners weakly acute, slightly recurved, apex with shallow off-center emargination with single, small, blunt median tooth, only very minor variation in shape observed among sites (e.g., Fig. 6B ); internal sac ( Fig. 6A ) with only obscure internal structure, with a weakly coiled basal pouch, an internal “hook” sclerite, and a tri-lobed apex, the median portion with a moderately well-sclerotized inner rod beneath a dimpled, membranous dome.

Adult Diagnosis. Within its limited range, there are very few other Paederinae that could be confused for M. icarus . The closest in morphology and range is Hypomedon rufipes ( Casey, 1905) , which is similar in size, coloration, and is also flightless, with short elytra and reduced eyes (and which may, in fact, represent a complex of similar species; unpublished data). Generally, H. rufipes occurs at lower elevations than M. icarus . However, the two do appear to co-occur at some middle-elevation sites, with H. rufipes known up to around 1,300 m, and M. icarus as low as ~ 900 m —both are found in the old-growth Joyce Kilmer Memorial Forest in far western North Carolina, for example (though not yet in any of the same exact samples). Males of the two are easy to distinguish, as H. rufipes lacks any palisade setae on sternite VII, though sternite VIII is similarly emarginate. The aedeagus of the two species is completely different, with that of H. rufipes elongate, tapered to near the apex, then with a knobbed, blade-like tip. In both sexes the basal metatarsomeres of H. rufipes are longer than those of M. icarus , nearly as long as metatarsomeres 2 and 3 combined, and the gular sutures are more widely separated at the base, most narrowly separated well forward of the middle of the bottom of the head. Generally, the body coloration of H. rufipes is lighter, more rufescent, though both species are somewhat variable. At higher elevations M. icarus is found in company with some flightless Lathrobium species, but these are significantly larger in body size, and none have the specialized setae of sternite VII.

Medon americanus was described from the eastern US (type locality “ Pennsylvania ”), but is so far only known from there and northward into Canada, so does not overlap at all in range. It is a somewhat larger, fully winged species with longer elytra, a more strongly quadrate head, a more distinctly toothed labrum, and distinctly transverse waves of microsculpture on the head and pronotum (minutely reticulate in M. icarus ). Its male genitalia are very similar to those of M. icarus , and given the variation in the latter, the two probably cannot be reliably distinguished on that basis. Male sternite VII of M. americanus may have more palisade setae (10 vs. 8 in M. icarus ) although samples have been inadequate to assess the consistency of that difference.

The Palearctic Medon fusculus (Mannerheim) , Medon apicalis (Kraatz) , and Medon ripicola (Kraatz) have all been reported in North America. but are apparently so far restricted to eastern Canada (Brunke and Marshall 2011; Pentinsaari et al. 2019), so would not be encountered in this range. Males of two of these, M. ripicola and M. fusculus , do have palisade setae on sternite VII, but all three are fully winged and easily distinguished on that basis. In addition, the introduced species all have coarse, umbilicate punctures on the head and pronotum, whereas those of M.icarus and M. americanus are finer and not umbilicate (A. Brunke, personal communication).

Larva. 1 st instar very lightly sclerotized ( Fig. 7A ), head light brown, legs and sclerites of body light gray, translucent; 2 nd instar with head and pronotal sclerite distinctly darker, other dorsal sclerites light brownish gray; head flattened, tapered anteriad (in lateral view), quadrate, sides weakly narrowed just before middle, with setae and pores as shown in Fig. 8 ; neck less than half as wide as head, bearing patches of egg-bursting setae ( Fig. 8A ) on either side, and a basal collar; 6 stemmata present behind mandibular insertions, a dorso-ventral arc of 4 in front of an obliquely longitudinal pair; posteriodorsad of stemmata a small pyramidal sensorium present bearing a long trichobothrium, with a dense cluster of minute teeth above; nasale weakly arcuate ( Fig. 8B ), with 4 blunt teeth on each side, the outer 3 with short, wide basal seta, the innermost tooth broader, short, with circular patch of minute sensory setae near its outer base, the two median teeth separated by a shallow emargination; median emargination with two small, approximate setae beneath, only barely projecting into base of emargination.

Mandibles ( Figs. 8A, C ) long, falcate, smooth (not serrulate) along inner margin, bearing a single seta near the base on the outer ventral edge. Antenna ( Fig. 8A ) with sensory appendage on inner margin of antennomere 3 nearly as long as terminal antennomere, characteristically curved laterad. Maxilla ( Fig. 8C ) with cardo short, widened from base to apex, apical margin with strongly projecting tooth overlapping base of stipes; stipes cylindrical, with conspicuous basolateral trichobothrium; mala digitiform, weakly curved, about as long as maxillary palpomere I; palpomere II slightly shorter than I or III; palpomere III bearing long terminal sensilla. Apotome of gula weakly separated from largely membranous submentum, bearing 2 small pores. Labium with mentum subquadrate, weakly widened at apex; ligula with wide basal sclerite, with elongate, bulbiform, membranous apex densely fimbriate; labial palpomere I twice as long and twice as wide as palpomere II; palpomere II bearing long sensilla at apex, appearing as a small third segment. Epipharynx ( Fig. 8B ) without lateral denticles; buccal opening with prominent row of teeth along anterior margin, 5 larger median teeth flanked and partially overlapped by shorter lateral ones; posteriad buccal opening are smaller lateral combs of fine denticles on either side of a sparser longitudinal field of fine, long cuticular processes.

Dorsal sclerites ( Fig. 8D ) TI–III with ecdysial lines along midline of body; prothorax narrowed to front, with prominent setae along posterior and lateral margins; TI with prominent median discal seta, prominent setae along posterior and lateral margins, and a trichobothrium near the posterolateral corner on a pyramidal base; thoracic tergites II and III similar in size and chaetotaxy, with one median and two lateral dominant setae, as in Fig. 8D ; series of very fine cuticular combs present in membrane between terga I and II and between TIII and AbI; tergites and ventrites of AbI–VIII divided along midline, with two small pleural sclerites per segment on each side; AbI with transverse, sclerotized carina along anterior margin of tergite; with similar combs on the median and lateral areas of main dorsal sclerites AbII–VII. Prosternum with dense field of minute setae along lower hypopleural margin; thoracic ventrites with few fine setae, particularly in precoxal area, ventrites I–VIII similar in chaetotaxy, as in Fig 8D ; basal segment of urogomphus about 1.5× as long as terminal segment, with prominent lateral setal bases; terminal segment of urogomphus slender, with one short dorsal seta and a single long terminal seta.

Larval Remarks. The larva of M. icarus conforms to diagnostic characteristics of Paederinae previously cited ( Kasule 1970; Newton 1990; Staniec et al. 2022), having three characteristic paired trichobothria on the basal corner of the stipes, on the side of head behind the ocelli, and at the posterolateral corner of the pronotum. It further conforms with diagnoses of Lathrobiini and Medonina presented in Staniec et al. (2022), having a relatively large maxillary mala, a bulbiform and fimbriate labial ligula, lack of lateral epipharyngeal denticles, and lacking a median tooth on the nasale. Some of these characters conflict with those described for M. “nr. johni ” in Frania (1986), which is described as having both mesal and lateral epipharyngeal denticles. Frania did not illustrate these for Medon specifically, however, so some ambiguity in just what was meant remains. The M. icarus larva also does not key directly to Medon in Staniec et al. (2022), as there is only a single row of teeth along the anterior margin of the buccal cavity. With only two larvae described from a diverse, Holarctic, and questionably monophyletic genus such as Medon , little more can be said about generic characterization.

Diagnosis from other co-occurring Paederinae larvae is complicated by generally poor documentation. Newton (1990) illustrated the larval head of Sunius confluentus (Say) , which is conceivably sympatric with M. icarus in some lower elevation localities. They are similar in gross structure, but the Sunius mandibles are illustrated as finely serrulate (which is also the case in Pseudomedon obsoletus (Nordmann) ; Staniec et al. 2022), whereas the inner margin is smooth in M. icarus .

Etymology. The name “ icarus ” calls to mind the proud Greek boy who flew too high and lost his wings, appropriate for this high-elevation, flightless (but proud) beetle. It is to be treated as a noun in apposition.

Figures

Fig. 4. Habitus and detail of external morphology of adult Medon icarus, new species. A) Dorsal view, B) Lateral view, C) Ventral view of apex of male abdomen, showing combs of ventrite VII, D) Ventral view of apex of female abdomen, E) Dorsal view of head and prothorax.

Fig. 5. Adult mouthparts of Medon icarus, new species. A) Left mandible, dorsal view, B) Labrum, dorsal view, C) Right mandible, dorsal view, D) Right maxilla, ventral view, E) Labium, ventral view, right palp omitted, F) Hypopharynx/ligula of labium, internal view.

Fig. 6. Aedeagus of Medon icarus, new species. A) Ventral view of “typical” form, from Clingmans Dome, NC, B) Ventral view of slight variant, from Grassy Ridge Bald, NC, C) Lateral view of “typical” specimen.

Fig. 7. Lateral habitus views of 1st instar larva of Medon icarus, new species. A) Pre-extracted, intact larva, B) Cleared larva, following proteinase digestion.

Fig. 8. Larval morphology of 1st instar Medon icarus, new species. A) Head, dorsal view, B) Detail of labrum (nasale) and epipharynx, external (dorsal) view, C) Head, ventral view, D) Selected thoracic and abdominal segments showing chaetotaxy, ventral view on the left, dorsal view on the right.