SCENOPINID.E 593 



IX. SCENOPINID^. 



Orthorrhaphous brachycerous practically eremochsetous flies of rather 

 small size; distinguished by their narrow oblong shape, dark colour, and 

 peculiar simple venation. 



Fig. 328.— Scenopinus fenestralis <} . x 8. 



Head semicircular, the arc being slightly flattened in front and almost straight 

 behind, not quite close to the thorax. Face broad but very short, quite bare ; frons 

 and vertex almost flush with the eyes, or so slightly sunk that the eyes cannot be 

 termed bulging ; ocelli three. Proboscis withdrawn, very short, with broad sucker- 

 flaps ; palpi cylindrical or slightly clavate, sparsely bristly at the tip. Eyes bare, 

 usually (but not always) touching in the male, but separated in the female by the 

 wide frons ; when the eyes touch the facets on more than the upper half are 

 enlarged ; in life they bear colored bands. Antennae three-jointed, close together at 

 the base ; basal joints short, but the third joint elongate strap-shaped, bent down- 

 wards, and without any distinct style or arista. 



Thorax oblong, being rather longer than broad, rather flattened on the disc and 

 yet appearing humpbacked because the head is depressed ; absolutely without 

 bristles, but with very short scaly pubescence on the disc, and with minute 

 pubescence on the pleurae ; metaj^leurse without any tuft or shelter hairs. 

 Scutellum broad, short, flat, and unarmed ; metanotum rather large but not 

 conspicuous. 



Abdomen flattened, with seven or eight segments but each segment bearing an 

 impressed transverse channel across its middle, and the membranes between some 

 of the segments usually bearing narrow white bands in the male. Genitalia of the 

 male rather knobbed ; ovipositor concealed. 



Legs usually short, stout, and entirely unarmed ; tibiae never spurred, though 

 some small bristles may have a spur-like appearance. Pulvilli two, small but 

 distinct ; empodium represented by a thin bristle only. 



Wings when at rest lying flat on the depressed abdomen ; veins few and simple ; 

 costal vein ending well before the wing-tip and not continued as an ambient vein 

 after the end of the discal vein ; subcostal vein short and simple ; radial vein also 

 short ; cubital vein forked, and the fork commencing nearly level with the end of the 

 discal cell ; all the veins down to and including the discal vein ending separately 

 and before the wing-tip ; discal cell oblong, emitting towards the wingmargin only 

 an upper veinlet and the end of the upper branch of the postical vein, as through 

 the complete absence of the small cross-vein this upper branch of the postical vein 

 formsthe whole of the lower margin of the discal cell ; posterior cells three only, 

 of which the first slopes upwards and is narr«jwed or even closed towards the wing- 

 margin and wholly reaches the wingmargin before the wing-tip (in ^S'. vai-vpes Loew 

 apparently at the exact wing-tip) ; discal cross-vein only slightly after the middle 

 of the discal cell and about the middle of the stem of the cubital vein, and conse- 



2p 



