Ceratopogon Meigen

Ceratopogon Meigen

(Figs. 13C, 15B, 19H–J, 24C, 29N, 32H, 35B, 43P–Q, 48C, 57C, 58A, 73J)

DIAGNOSIS: Only pupa of Ceratopogonidae with the dorsal apotome with a pronounced central dome from which both dorsal apotome setae arise (Figs. 19H–J); also unique in having an inner tracheal tube of the respiratory organ strongly hooked apically, appearing as an inverted "J" (Figs. 43P–Q).

DESCRIPTION: Total length = 1.88–3.38 mm. Without larval exuviae retained on abdomen. Exuviae with flagellum appressed against lateral margin of face (Fig. 15B). Ecdysial tear medial or posteromedial to base of antenna (Figs. 15B, 79D); along prothoracic extension. Head: Dorsal apotome (Figs. 19H–J), without ventral line of weakness, without dorsomedial tubercle, with central dome; dorsolateral cephalic sclerite (Fig. 13C) separated from scutum by thin cuticle, separate from scutum upon emergence, each side separated medially by dorsal apotome in whole pupa; mouthparts (Fig. 24C) with only mandible or mandible ventral to lacinia; palpus extending equal to or just posterior to posterolateral margin of labium; labium separated medially by labrum, hypopharynx; apex of antenna (Fig. 35B) anterior to posterior extent of midlength portion of midleg (portion lateral to mesosternum); sensilla: dorsal apotomals (Figs. 19H–J)—1 elongate seta, 1 campaniform sensillum; dorsolateral cephalic sclerite sensilla—1 seta, 1 campaniform sensillum; clypeal-labrals (Fig. 24C)—2 short, slender setae; oculars (Fig. 24C)—2 setae, 1 campaniform sensillum. Thorax: Prothoracic extension (Fig. 24C) wide, welldeveloped, extending from palpus to antenna; mesonotum with short tubercles, not extending posteromedially or with slight protuberance, not dividing metathorax medially (Fig. 48C); respiratory organ (Figs. 43P–Q) length/ width = 2.74–3.68, moderately elongate, apical half somewhat flattened dorsoventrally, with pores closely abutting or slightly separated at apex of respiratory organ, arranged in single straight or curve row, outer surface smooth or with some wrinkles, with or without short, wide pedicel, base with slender, strung out posteromedial apodeme, membranous base of respiratory organ short, tracheal tube apically J-shaped, surface smooth or distally with plates; wing (Fig. 35B) without apical tubercle or angle, separated medially by fore-, midlegs; halter apex and hind leg (Fig. 32H) just separate; halter apex abutting anterolateral knob-like extension of tergite 2; legs (Fig. 35B) with lateral margin of foreleg near midlength of wing evenly curved; hind leg visible at lateral margin of wing (Fig. 32H); with apex of foreleg ventral to or moderately anterior to apex of midleg; apex of hind leg slightly dorsal to, partially abutting apex of midleg laterally; sensilla: anteromedials—1 seta; anterolaterals—2 setae; dorsal setae (Fig. 29N)—D-1-T, D-2-T, D-4-T, D-5-T setae, D-3-T campaniform sensillum, D-3-T posterior to D-4-T; supraalar 2—campaniform sensillum; metathoracics (Fig. 48C)—1 seta, 2 campaniform sensilla; M-3-T near anterior margin of metathorax. Abdomen: without pigmentation pattern or pigmentation patterns only evident in alcohol/ glycerin material, with tergite 1 with 3 medial spots, tergites 2–8 with 3 medial spots, anterolateral spots, sternites 3–7 with medial spot, anterolateral spot, segment 2 as wide or slightly wider than segment 3, segments with undivided, thin to thick setae, with bilobed, short and triangular to elongate and slender tubercles, tergites or sternites entire, each without membranous disc; segment 9 (Fig. 73J) not strongly modified, terminal processes closely approximated basally, each projecting posterodorsolaterally to nearly laterally, tapering to pointed apex; sensilla: tergite 1 (Fig. 48C) with 6 setae, 2 campaniform sensilla, including 3 lateral sensilla, D-2-I, D-3-I closely approximated, D-7-I situated posteriorly near D-8-I; segment 4 (Figs. 57C, 58A)—D-2-IV, D-3-IV setae on either short tubercle, bilobed or bifid elongate tubercles; D-5-IV present or absent, D-8-IV, D-9-IV short to elongate setae; each at base of short bilobed or elongate bifid, separate tubercles, posterior dorsal sensilla in transverse row, arranged medially to laterally: D-5-IV, D-4-IV, D-7-IV, D-8-IV, D-9-IV or D-5-IV absent and D-7-IV anterior to D-9-IV; L-1-IV short seta at base of short bilobed or elongate bifid tubercle, well anterior of posterior lateral setae; L-2-IV, L-3-IV, L-4- IV short setae at base of bilobed elongate bifid tubercles, V-5-IV, V-6-IV, V-7-IV on bilobed or at base of bifid, elongate tubercles; segment 8 without D-3-VIII, without L-1-VIII; segment 9 (Fig. 73J)—with D-5-IX, D-6-IX campaniform sensilla.

DISTRIBUTION AND HABITAT: The genus Ceratopogon is known from 43 species in the Holarctic Region with adults emerging in cold environments (Arctic, mountainous, or in early spring) (Borkent & Grogan 1995). Immatures have been found in moss in cold forest pools, at the margins of shallow water bodies, bogs, fens, in moist soil, on flood plains and on lake shores.

TAXONOMIC DISCUSSION: Six species of Ceratopogon are known as pupae (Tables 2–3) and the five Nearctic ones are keyed by Borkent & Grogan (1995) as part of a comprehensive revision of the genus.

Ceratopogon boomerangus is the only member of the genus missing the full complement of abdominal sensilla present in most Ceratopogonidae (and all other Ceratopogon), with fourth abdominal segment sensillum D-5-IV absent. The figure of the fourth abdominal segment of C. boomerangus shown in Fig. 57C (from Borkent & Grogan 1995) is distorted by compression and the distribution of the sensilla are broader than is natural (i.e. the dorsal and ventral sensilla are actually more lateral, L-1-IV, L-2-IV and L-3-IV are shown as ventral). This is true for all the species illustrated by Borkent & Grogan (1995:183). The fourth abdominal segment of C. nr. inverecundus in Fig. 58A was drawn from an uncompressed specimen in glycerin.

Mayer (1934a:238) described a pupa referred to as "Genus incertum" from Germany which was reexamined for this study. It is a species of Ceratopogon but cannot be identified to species at present.

MATERIAL EXAMINED: C. abstrusus: 1 pupal exuviae (of paratype), Sand Pond Br., Blue Ridge, New York, USA, 26-V-1959 (NYSM); 1 pupal exuviae (of paratype), The Gulf Brook, Blue Ridge, New York, USA, 25- V-1958 (NYSM); 1 pupal exuviae (of paratype), New York (?) (NYSM); 1 pupal exuviae (of paratype), Hamilton-Essex, Newcomb, New York, USA, 28-V-1959 (NYSM). C. arcanus: 2 pupal exuviae (of paratypes), Fishing Creek, Newcomb, New York, USA, 5-V-1958 (NYSM); 2 pupal exuviae (of paratype), Huntington Rd. Marsh, Newcomb, New York, USA, 14-V-1958 (NYSM); 1 pupal exuviae (of paratype), Blue Mountain Lake, New York, USA, 3-V-1960 (NYSM); 1 pupal exuviae (of paratype), High Rock Pond outlet, Inlet, New York, USA, 8-V-1958 (NYSM); 2 pupal exuviae (of paratypes), Hamilton-Essex, Newcomb, New York, USA, 11-V-1959 (NYSM). C. boomerangus: 1 pupal exuviae (of allotype), College Park, Prince George County, Maryland, USA, 14-IV-1976 (USNM). C. inverecundus: 2 pupal exuviae (of paratypes), Edge 6 Mile Creek, Long Lake, New York, USA, 18-V- 1959 (NYSM). C. naccinervis: 1 pupal exuviae, Severskii Donets River, Donetsk Province, Ukraine, 16-IV-1970 (ZIN). C. willisi: 1 pupa (paratype), College Park, Prince Georges County, Maryland, 17-III-1976 (USNM); 1 pupa (paratype), as previous locality, 26-III-1976 (USNM). C. nr. abstrusus: 1 pupal exuviae (in glycerin), 2 pupal exuviae, Bolean Lake, 6 km NE Falkland, BC, Canada, 12-13-VII-1989 (CNCI). C. nr. inverecundus: 1 pupal exuviae (in glycerin), 1 pupal exuviae, Bolean Lake, 6 km NE Falkland, BC, Canada, 12-13-VII-1989 (CNCI). C. sp.: 1 pupa, Haspertalsperre Sauerland, Westfalen, Germany 1-VI-? (ZSMC).