232 



LEPTID^ 



III. LEPTID^. 



Orthorrhaphous brachycerous eremochfetous flies of rather small to 

 rather large size and of more or less elongate shape ; usually thinly pilose 

 or almost bare, and with the tibia3 (or at least the posterior pairs) always 

 spurred; ambient vein entire, and the squamae small. 



Fig. liiO, —Lcj^tis scolopacea ^ . x 3. 



Head semicircular, usually very short and flattened in front, and consequently 

 with an upturned appearance (though drooped in Coenomyia) ; sometimes as broad as, 

 but often narrower than, the thorax. Frons at the vertex almost flush with the eyes ; 

 face usually with a socketed middle part (epistoma) on which there is usually a 

 rounded raised tubercle, and with large side-cheeks or sideraargins which may bear 

 long dense pubescence or which may be quite bare, but sometimes the face has no dis- 

 tinct side-cheeks and no central tubercle ; face usually very short, so that the antennae 

 are placed near the mouth or at least as low as the luiddle of the head. 

 Proboscis usually rather large and stout, with large sucker-flaps, but in Lampromyia 

 (fig. 167) remarkably long; palpi long and slender, jointed. Eyes bare (except in 

 Coetiomj/ia), usually approximated or touching in the male but more or less widely 

 sepai'ated in the female, and not bulging above the level of the vertex as in Asilidce, 

 but sometimes (Xylophag^is) the eyes are almost equally separated in both sexes ; 

 facets in the male sometimes considerably and conspicuously enlarged on the upper 

 part ; eyes in life Avhole colored, sometimes brilliant green. Antennae in typical 

 Leptldd' with the third joint simple, short conical, round, or reniform, with a 

 terminal bristle or style, and when the joint is reniform the arista may ajipear to 

 be dorsal (fig. 1 70) ; while in the aberrant subfamilies the antennte may have the 

 third joint flagelliform and annulated {Caenomyimc, Xi/h/)har//n(i^). 



Thorax normal in shape and almost always bearing moderate or even almost 

 bristly short pile without any trace of strong bristles ; metapleurse ordinarily with 

 a rather dense tuft of pubescence ; prothoracic plate forming an elongate triangle 

 or at any rate pointed below. 8cutellum usually large and bearing slightly 

 lengthened bristly hairs, unarmed (except in Ccenomj/ia) and not elongate ; 

 metanotum usually rather concealed beneath the large scutellum, but unusually 

 large and conspicuous in VermiJeonince and Xj/Iopha(iinre. 



Abdomen with seven olivious segments besides the genitalia, always more or 

 less elongate, and often conical ; jjubescence modei'ate, never bristly and never 

 furry, but rarely absent. 



Legs usually rather long, without any strong bristles or even distinct small 



