Serromyia Meigen

(Figs. 20G, 25D, 30A, 36D, 44N, 49D, 60C, 74H)

DIAGNOSIS: Only pupa of Ceratopogonidae with abdominal segment 4 sensilla L-1-IV, L-2-IV and L-3-IV close together on a rounded tubercle (Fig. 60C).

DESCRIPTION: Total length = 3.10–4.19 mm. Without larval exuviae retained on abdomen. Exuviae with flagellum appressed against lateral margin of face, midleg, wing (as in Figs. 15D, 33B). Ecdysial tear medial to base of antenna (as in Figs. 15D, 79D). Head: Dorsal apotome (Fig. 20G), without ventral line of weakness, with short dorsomedial tubercle, without central dome; dorsolateral cephalic sclerite (as in Fig. 13B) separated from scutum by thin cuticle, but partially fused to scutum upon emergence, each side separated medially by dorsal apotome in whole pupa; mouthparts (Fig. 25D) with mandible well-developed, lacinia absent; palpus extending posterior to posterolateral margin of labium; labium entire (not divided medially); apex of antenna (Fig. 36D) anterior to posterior extent of midlength portion of midleg (portion lateral to mesosternum), narrowed posteriorly; sensilla: dorsal apotomals (Fig. 20G)—1 short seta, 1 campaniform sensillum; dorsolateral cephalic sclerite sensilla—1–2 short setae (1 specimen with one very short, 1 elongate seta), 1 campaniform sensillum; clypeallabrals (Fig. 25D)—absent; oculars (Fig. 25D)—1 campaniform sensillum. Thorax: Prothoracic extension (Fig. 25D) wide, well-developed, extending from palpus to antenna; mesonotum with short tubercles, not extending posteromedially, not dividing metathorax medially (Fig. 49D); respiratory organ (Fig. 44N) length/width = 2.64–4.09, moderately elongate, wide apically, somewhat flattened laterally or circular in cross-section, with pores closely abutting or slightly separated at apex of respiratory organ, arranged in single row, outer surface smooth, with short, wide pedicel, base without posteromedial apodeme, membranous base of respiratory organ moderately elongate, tracheal tube straight to slightly curved along length, with spirals restricted to base or to half length, distally with plates; wing (Fig. 36D) without apical tubercle or angle, separated medially by fore-, midlegs; halter apex and hind leg (as in Fig. 33A) broadly abutting; halter apex abutting anterolateral knob-like extension of tergite 2; legs (Fig. 36D) with lateral margin of foreleg near midlength of wing evenly curved; hind leg visible at lateral margin of wing (as in Fig. 32L); with apex of foreleg moderately anterior to apex of midleg; apex of hind leg abutting apex of midleg laterally; sensilla: anteromedials—1 seta; anterolaterals—1 seta; dorsal setae (Fig. 30A)—D-1-T, D-2-T, D-4-T, D-5-T setae, D-3-T campaniform sensillum; D-1-T, D-2-T on single tubercle, D-3-T posterior to D-4-T; supraalar 2—campaniform sensillum; metathoracics (Fig. 49D)—1 small seta, 2 campaniform sensilla; M-3-T near anterior margin of metathorax. Abdomen: without pigmentation pattern, segment 2 as wide or slightly wider than segment 3, segments with undivided, thin to thick setae, with rounded short tubercles, tergites or sternites entire, each without membranous disc; segment 9 (Fig. 74H) not strongly modified, terminal processes closely approximated basally, each projecting posterodorsolaterally, tapering to pointed apex; sensilla: tergite 1 (Fig. 49D) with 8 setae, 2 campaniform sensilla, including 4 lateral sensilla, D-2-I, D-3-I closely approximated, D- 7-I situated anterolaterally near L-1-I; segment 4 (Fig. 60C)—D-2-IV peg-like seta, D-3-IV short slender setae, on rounded tubercles; D-5-IV, D-8-IV short setae, D-9-IV absent; D-5-IV on short separate tubercle, D-4-IV and D-8- IV on short separate tubercle, posterior dorsal sensilla in transverse row, arranged medially to laterally: D-5-IV, D- 4-IV, D-8-IV; D-7-IV near L-1-IV; L-1-IV on rounded tubercle with L-2-IV, L-3-IV all short setae, L-4-IV on short tubercle, V-5-IV, V-6-IV, V-7-IV short setae, on rounded tubercles, V-5-IV, V-6-IV on single tubercle; segment 8 without D-3-VIII, without L-1-VIII; segment 9 (Fig. 74H)—with D-5-IX, D-6-IX campaniform sensilla.

DISTRIBUTION AND HABITAT: The genus Serromyia is known from 35 species from every Region worldwide other than the Neotropical Region ( Borkent & Bissett 1990; Borkent 2014). Species have been collected from bogs, fens, wet meadows, streams or small rivers. At least within the Holarctic Region, species are restricted to wooded areas. Strenzke (1950) and Thienemann (1950) found immatures in mosses at lake margins in Germany and Kettle & Lawson (1952) found larvae in mud associated with marshlands.

TAXONOMIC DISCUSSION: There are only two species of Serromyia known as pupae (with one of these actually of uncertain identity) (Tables 2–3).

Of the five specimens of Serromyia available for study, one was of S. atra and previously studied by Borkent & Bissett (1990). It included a pharate adult, ensuring correct identification of this specimen. Of the remaining specimens, three were of pupal exuviae and one of a whole pupae, all previously slide mounted, with old, similar labels (perforated edges), with the same handwriting (likely that of Thienemann), and at least one collected by Strenzke (1950, site 220, Grosser Ukleisee, Germany), with the notation "gez." (short for gezüchtet, meaning reared). Strenzke (1950:349) noted that larvae were "not rare in damp mosses [in German]". All were previously identified as S. femorata (probably by Strenzke), even though no associated adult material was present. The pupa was young, so there were no pharate adult features to be studied. As such, there is a level of uncertainty as to both the species identification ( Borkent & Bissett 1990) as well as the generic identity. However, it appeared that all four were conspecific and Strenzke likely correctly identified the emerged adults as Serromyia, considering their distinctively fat and spinose hind femora. The pupae also matched the description of S. femorata by Kettle & Lawson (1952) and were very similar to that of S. atra, further suggesting that the generic identification of these specimens is correct.

Borkent and Bissett (1990) missed the sensillum coeloconica D-7-IV on abdominal segment 4 of the Serromyia pupa they illustrated.

MATERIAL EXAMINED: S. atra: 1 pupa, Schöhsees, Germany (ZSMC). S. femorata: 1 pupa, 2 pupal exuviae, no locality, date (likely Thienemann collection, ZSMC); 1 pupal exuviae, Grosser Ukleisee, Germany (likely Thienemann collection, ZSMC).