Insulestremia Jaschhof, 2004

Carmo-Neto, Antonio Marcelino Do, Lamas, Carlos José Einicker & Urso-Guimarães, Maria Virginia, 2021, Review of Insulestremia Jaschhof, 2004 (Diptera; Cecidomyiidae; Lestremiinae) with description of two new species from Brazil, Zootaxa 4966 (3), pp. 367-375 : 368-369

Genus Insulestremia Jaschhof, 2004

Type species: Insulestremia sinclairi Jaschhof, 2004 (orig. des. and mon.)

Male. Head: Postcranium with irregularly arranged long setae. Two ocelli. Antenna with scape somewhat larger than pedicel, both setose ventrally. 14 flagellomeres; each but terminal flagellomere with distinct neck; node of flagellomere 4 completely covered with microtrichiae; with 1 complete and 1-2 incomplete crenulate whorls of long sensory hairs; distally a few short hair-shaped translucent sensilla, sensory pegs and 1‒3 flattened sensilla, of which one may be two-pointed, arising from a very large basal pore ( Figs. 1A , 2A ); flattened translucent sensilla absent on more distal flagellomeres, starting with the 6 th. Face non-setose. Clypeus largely fused with face, small, with long setae. Maxillary palpus 4-segmented (excluding small, smooth and non-setose presegment), setose; segment 1 thickest, with numerous translucent sensilla; segments 2–4 cylindrical, increasing in length.

Thorax: Postpronotum forming well developed bulge above neck. Antepronotum long and narrow, bare. Proepisternum long, bare. Proepimeron barely traceable. Scutum with dorsal surface evenly arched to slight degree; with anterior parapsidal suture weak, no median transverse suture traceable, and bearing lateral and dorsocentral rows of setae. Paratergite distinct from scutum and well sclerotized. Scutellum setose. Mediotergite short. Postphragma large, intruded into abdominal cavity for at least half the length of abdominal segment 1. Laterotergites unpronounced. Anepisternum subtriangular, much smaller than katepisternum; the latter subtriangular ventrally. Pleural pit indistinct. Epimeron not subdivided into anterior and posterior portions. Metanotum not traceable. Metepisternum high, not subdivided. Metepimeron not traceable. Wing: Blade rather short and broad. Calypteral area not lobed. Anal lobe pronounced. Membrane transparent, evenly covered with setae. Venation: C with break clearly before wing apex; Sc long, ending free; R1 very short; Rs and rm extremely short; M1+2–fork longer than stem, diverging in distal third; M4 free proximally; CuP traceable as row of setae. M and CuA wide but pale. Setae along wing margin and dorsally on Sc, R, R5, M1+2-stem and fork, M4, CuA, CuP, and on R5 also ventrally. Halter club-shaped with comparatively short stem, with short setae in medial portion. Legs: Longer than body, with short setae most dense on tarsi. Coxae shorter than half height of thorax. Tarsomeres 1–4 decreasing in length, tarsomeres 4 and 5 subequal in length. Tarsal claws crescent-shaped, bent at midlength. Empodia half the length of claws. Pulvilli not traceable.

Abdomen: Segment 1 very short. All sclerites but sternite 1 setose. Pattern of tergal Plaques: 0/1–2/1– 2/1/1/1/1/0. Terminalia: Gonocoxal synsclerite setose except a large portion ventroproximally, with the ventral emargination either concave and not extending beyond midlength of gonocoxites ( Fig. 1A ) or convex ( Fig. 2A ); a dorsomedial lobe may be present; dorsal transverse bridge complete, well sclerotized, at a right angle in relation to the gonocoxal apodeme. Gonostylus large, bilobed; posterior lobe more robust, thicker, with setae of various sizes including conspicuously strong ones (megasetae) apically, varying in size relative to medial lobe ( Figs. 1A , 2A ); medial lobe straight or slightly bent inwards, tapered apex, with small tooth, which is either spine-like ( Fig. 1A ) or fingernail-like ( Fig. 2A ) and always surrounded by a few short spines, setae of various lengths elsewhere; lobes perpendicular in the vertical axis. Tegmen variable in width, with clear contours; parameral apodemes thick, well sclerotized ( Figs. 1A , 2A ); anterior portion of gonocoxal apodemes just traceable. Ejaculatory apodeme long, sclerotized, without any modifications. Tergite 9 short, setose; posterior edge broadly rounded, anterior edge sharply contoured. Cerci comparatively short, subtriangular, setose. Hypoproct one-lobed, pubescent.

Female. Head: 9 flagellomeres, each with very short stem and subcylindrical to barrel-shaped node ( Fig. 1C ); nodes with 2‒4 flattened, one- to four-pointed translucent sensilla arising from large basal pores. Terminalia: Ovipositor short, without striking modifications. Sclerotized spermathecae absent.

Diagnosis. Insulestremia is defined by male genitalic characters, as follows. It is the only lestremiine genus in which the dorsal gonocoxal bridge is uniformly sclerotized, i.e. not interrupted medially. The anterior portions of the gonocoxal apodemes (“dorsal parameral apodemes” in Jaschhof (2004)) are vestigial. The bilobed gonostylus consists of the posterior lobe bearing one to several megasetae apically and the elongate medial lobe bearing a small tooth; lobes perpendicular in relation to each other.

Figures

FIGURE 1. Insulestremia amorimi, male: A) terminalia, ventral view; in blue, ejaculatory apodeme; in green, tegmen; in orange, hypoproct; in red, cerci; B) male flagellomeres 3 and 4; C) female flagellomere 4. Scale bars: 50 µm. Abbreviations: ga, gonocoxal apodeme (posterior portion); pa, parameral apodeme; tb, transverse bridge; t9, tergite 9.

FIGURE 2. Insulestremia amenti, male: A) terminalia, ventral view; in blue, ejaculatory apodeme; in green, tegmen; in orange, hypoproct; in red, cerci; B) male flagellomere 4. Scale bars: 50 µm.