Pachyhelea Wirth

Pachyhelea Wirth

(Figs. 22G, 28F, 31G, 41C, 46M, 53F, 70B, 77K–L)

DIAGNOSIS: Only pupa of Ceratopogonidae with dorsal apotome with only one campaniform sensillum (Fig. 22G), metathorax with only one campaniform sensillum (M-3-T) situated at least ⅓ the length of the metathorax from its anterior margin (Fig. 53F), apex of the halter extending posteriorly to about 1/6 length of tergite 2 (as in Fig. 33L), L-1-IV and L-3-IV short setae on separate tubercles, L-2-IV well separated from L-3-IV, V-7-IV is closer to L-4-IV than to V-5-IV and V-6-IV, which are closely abutting (Fig. 70B).

DESCRIPTION: Total length = 7.22 mm. Without larval exuviae retained on abdomen. Exuviae with flagellum appressed against lateral margin of midleg, wing (as in Figs. 16B, 33B). Ecdysial tear around base of antenna, along lateral margin of face to palpus (as in Figs. 17C, 79H). Head: Dorsal apotome (Fig. 22G), uncertain ventral line of weakness, without dorsomedial tubercle, without central dome; dorsolateral cephalic sclerite (as in Fig. 13H) fused to scutum, each side separated medially by dorsal apotome in whole pupa; mouthparts (Fig. 28F) with mandible well-developed, lacinia absent; palpus extending posterior to posterolateral margin of labium; labium separated medially by labrum, hypopharynx; apex of antenna (Fig. 41C) barely anterior to posterior extent of midlength portion of midleg (portion lateral to mesosternum), narrowed posteriorly; sensilla: dorsal apotomals (Fig. 22G)—1 elongate seta, 1 campaniform sensillum; dorsolateral cephalic sclerite sensilla—1 seta, 1 campaniform sensillum; clypeal-labrals (Fig. 28F)—2 slender setae; oculars (Fig. 28F)—1 seta, 1 campaniform sensillum. Thorax: Prothoracic extension (Fig. 28F) wide, well-developed but very narrow dorsolaterally, extending from palpus to antenna; mesonotum without tubercles, not extending posteromedially, not dividing metathorax medially (Fig. 53F); respiratory organ (Fig. 46M) length/width = 3.96–5.00, elongate, moderately slender, somewhat flattened apically, with pores closely abutting at apex of respiratory organ, arranged in single row, outer surface with some wrinkles, with short, wide pedicel, base with elongate posteromedial apodeme, membranous base of respiratory organ short, annulated, tracheal tube straight to slightly curved along length, with spirals restricted to base, wrinkles to half length; wing (Fig. 41C) with short tubercle at apex of hind leg, separated medially by fore-, midlegs; halter apex and hind leg (as in Fig. 33J) broadly abutting; halter apex extending posteriorly to 1/6 length of tergite 2; legs (Fig. 41C) with lateral margin of foreleg near midlength of wing evenly curved; hind leg visible at lateral margin of wing (as in Fig. 33J); with apex of foreleg moderately anterior to apex of midleg; apex of hind leg abutting apex of midleg laterally; sensilla: anteromedials—2 elongate setae, 1 campaniform sensillum (as in Figs. 31L–M); anterolaterals—1 moderately long seta; dorsal setae (Fig. 31G)—D- 1-T, D-2-T, D-4-T, D-5-T setae, D-3-T campaniform sensillum, D-3-T lateral to D-4-T; supraalar 2—campaniform sensillum; metathoracics (Fig. 53F)—1 campaniform sensillum; M-3-T distant from margin of metathorax (at least 1/3 length of metathorax). Abdomen: with tergite 1 with 3 medial spots, tergites 2–7 with medial area with stripe, 2 anterolateral spots, sternites 3–7 with medial stripe, anterolateral spot; sternite 8 with dark posteromedial apodeme, segment 2 as wide or slightly wider than segment 3, segments with undivided, thin to thick setae, with rounded to pointed, short tubercles, tergites or sternites entire, each without membranous disc; segment 9 (Figs. 77K–L) not strongly modified, terminal processes separated basally, each projecting posterodorsolaterally, tapering to pointed apex; sensilla: tergite 1 (Fig. 53F) with 7 setae, 3 campaniform sensilla, including 3 lateral sensilla, D-2- I, D-3-I closely approximated, D-7-I situated anteriorly near D-3-I; segment 4 (Fig. 70B)—D-2-IV, D-3-IV short to moderately elongate setae, D-2-IV on short tubercle, D-5-IV very short seta, D-8-IV, D-9-IV short setae; D-5-IV without tubercle, D-8-IV, D-9-IV on separate but closely approximated tubercles, posterior dorsal sensilla in transverse row, arranged medially to laterally: D-5-IV, D-4-IV, D-8-IV, D-9-IV; D-7-IV near D-3-IV; L-1-IV short seta on rounded tubercle, near L-3-IV; L-2-IV, L-3-IV, L-4-IV short setae, L-2-IV, L-3-IV on very short tubercles, L-4-IV on pointed, elongate tubercle, V-5-IV, V-7-IV short setae, V-6-IV moderately elongate, on short tubercles, V-5-IV, V-6-IV closely approximated, V-7-IV closer to L-4-IV; segment 8 without D-3-VIII, without L-1-VIII; segment 9 (Figs. 77 K-L)—with D-5-IX, D-6-IX campaniform sensilla.

DISTRIBUTION AND HABITAT: The genus Pachyhelea is known from two species in the Nearctic and Neotropical Regions (Borkent 2014). The pupa of the only known species was collected in shallow water among filamentous algae (Spirogyra majuscula).

TAXONOMIC DISCUSSION: One species of Pachyhelea is known as a pupa (Tables 2–3).

MATERIAL EXAMINED: P. pachymera: 1 pupal exuviae, Arroyo Zapata, Partido de Magdalena, Provincia de Buenos Aires, Argentina, 23-XI-1981 (MLPA); 1 pupal exuviae, as previous locality, 24-XII-1981 (MLPA); 1 pupal exuviae, Santa Ana, Entre Rios, Argentina, 9-XI-1984 (MLPA).