Gobryidae, McAlpine, 1997

McAlpine, David K., 1997, Gobryidae, a new family of acalyptrate flies (Diptera: Diopsoidea), and a discussion of relationships of the diopsoid families., Records of the Australian Museum 49 (2), pp. 167-194 : 182-183

Gobryidae n.fam.

Type genus: Gobrya Walker

Diagnostic description. Fully winged, moderately small, elongate flies, with reduced chaetotaxy and somewhat braconid-like habitus. Head large, somewhat depressed, much broader than thorax; postfrons oblong, its surface entirely occupied by a uniformly sclerotised plate apparently derived from ocellar plate or triangle, with fine setulae at orbital margins; frontal lunule largely concealed; ptilinal fissure short, its descending lateral arms undeveloped; facial region broad, uniformly sclerotised, convex in profile, its lower part extensively facing ventrally; parafacial suture obsolete; upper occiput concave; supracervical region with compact, convex setulose callosity; eye large, much broader than postfrons in dorsal view; ocelli well developed, posterior ones on ridge of vertex; inner and outer vertical bristles present, the former much, the latter slightly behind ridge of vertex; other cephalic bristles absent; membranous subcranial region small, broadly oval. Antenna: segment 1 short; segment 2 short, deeply slit dorsally, with distal surface facing forwards; segment 3 elongate, deflexed at angle to rest of antenna, with dorsobasal process inserted into cavity of segment 2; arista unsegmented, probably through desclerotisation of segments 4 and 5, so that segment 6 appears to arise from a gibbosity on segment 3 a little beyond basal process of latter; segment 6 irregularly bipectinate, with dorsal rays more numerous than ventral ones densely pubescent on basal part. Prelabrum (postclypeus) short and deep; palpus and proboscis moderately developed; labella well developed, reflexed.

Thorax elongate, without neck-like anterior extension; pronotum very short; prosternal region with large basisternal plate, raised and medially grooved posteriorly, with very broad, largely ventrally facing precoxal bridges anteriorly; scutellum short; subscutellum distinct, convex, but not very prominent; prothoracic spiracle vertically elongate; narrow oblique sclerite (remnant ofkatepimeron) sharply demarcated from upper part of meron (meropleurite) by a well defined membranous strip; metathorax forming a prominent base for hind coxae, not cylindrically produced at attachment of abdomen (in contrast to Syringogastridae and Diopsidae ); postcoxal bridge deep, but deeply sinuate on dorsal side; apical scutellar, posterior notopleural (not on callosity), and sometimes anterior notopleural bristles present; postalar bristle either undifferentiated or small but distinct, located on angle of postalar callus and not dorsomedially displaced (i.e. located as in Syringogastridae , not as in Diopsidae ); scutellar bristle inserted on very slight tubercle; other thoracic bristles absent or scarcely differentiated from setulae. Legs of moderate proportions, but markedly increasing in length in the order fore, mid, hind; fore coxa slightly longer than hind coxa, inserted far from anterior end of thorax (but less far than in Nothybidae ); hind femur with thickened, spinescent seriate anteroventral and posteroventral bristles; other femora often with less developed ventral spinescent bristles; mid tibia with large apical ventral spur; tibiae otherwise without bristles; fore and mid tarsi much more slender than hind one; basitarsi cylindrical, without series of short cuneate setulae (in contrast to Syringogastridae and Diopsidae ). Wing narrow, attenuated basally; tegula very small; anterodorsal costagial bristle usually present but weak; costa extending to vein 4, without break or visible weakening at either humeral or subcostal position, with numerous fine setulae, but no stouter spines or spinules; subcosta complete, well sclerotised, terminating well before end of vein I so as to leave a clear subtriangular area of subcostal cell between the two veins; second basal, discal, and anal cells all elongate and complete; distal section of vein 6 well sclerotised but rather short, sometimes reaching approximately to wing margin; vein 7 indistinguishable beyond alular incision; alula much reduced, with incomplete marginal fringe; squama (lower calypter) quite undeveloped.

Abdomen very slender, with anterior segments forming a slender petiole which is more pronounced in male; abdomen dorsoventrally compressed at its hinge-like articulation with thorax; tergite I and sternite I with deep membranous sinuation in anterior margin (as component of hinge mechanism, in contrast to that of Syringogastridae and Diopsidae ); tergites I and 2 quite fused; other preabdominal tergites well separated by intersegmental membrane (in contrast to Syringogastridae ); sternites I to 5 all separate and well sclerotised; spiracles of segments I to 5 all located in pleural membrane, that of segment I well removed from margin of tergite.

Male postabdomen. Protandrium with single asymmetrical sclerite, apparently consisting of fused tergite 6 and sternites 6, 7, and 8, enclosing two pairs of spiracles (6 and 7). Epandrium large, asymmetrically subspherical; surstyli separated from margin of epandrium by membrane, very asymmetrical and of unequal size; a separate, undivided, plate-like subepandrial sclerite present between bases of surstyli; hypandrium desclerotised; aedeagus short and broad, with very complex, irregular, asymmetrical sclerotization; aedeagal apodeme absent; ejaculatory sclerite rather small, slender, bent near middle; cerci well developed, separate but attached to sides of proctiger, only slightly asymmetrical.

Female postabdomen short, not markedly extensile. Segment 6 large, with tergite and sternite fused into a complete ring (its form suggesting that it consists very largely of tergite), enclosing spiracle laterally; segment 7 shorter, with separate tergite and sternite and spiracle enclosed in tergite; cerci separate, very broad; spermathecae 3, with pigmented cuticular lining to vesicles (at least in G. cyanea ).