NOKTII AmKKK AN Dll'TKKA. 39 



hraiuli tcriniiiatinjj; beyond the tip ; five posterior cells ; basal cells 

 long, the third (anal) closed in the border. 



Predaceous flies, concealing themselves among the leaves of low 

 bushes whei'e they lie in wait for other insects. Larvae long, snake- 

 like, apparentlj- composed of nineteen segments; those of the known 

 species found in fungi or decaying wood ; pupaj free. 



1. Antennae situated upon a frontal projection, the first joint elon- 



gate and more or less thickeneil, longer than the head. 



Xkstomyza 



Kront not projecting; first joint of the anteiniie usually slender, 



when thickened, never longer than the head. . 2 



2. Face thickly pilose. ....... Thekeva 



Face bare Psilocephala 



Xestomyza Wiedemann, Nova Dipt. Gener 1820. 

 Thekeva Latreille, Precis, etc. 1796. 

 PsiLOCEPUALA Zetterstedt, Ins. Lapp. 525, 1840. 



SCKNOPINID^E. 



Small, slender, bare Hies. Males usually holoptic ; the front in 

 neither sex excavated. Ocelli present. Antenna? composed of three 

 simple joints, without style or bristle, the third joint elongate. Pro- 

 boscis short, concealed. Legs rather short ; empodia wanting. 

 Third longitudinal vein furcate ; three posterior cells, the first nar- 

 rowed or closed in the margin ; basal cells elongate, the first much 

 longer than the second, anal cell closed before the margin. 



Flies not rare in dwellings on windows. Larvae similar to those of 

 the There vidae; carnivorous, living in decaying wood, under car- 

 pets, etc SCENOPINUS 



SiENOPiNis Latreille, Hist. Nat. d. Ins. et Crust. XIV, 392, 1803. 



ACROCERIDvE. 



Small to large, never elongate, pilose or bare species. Head small, 

 or very small ; thorax large, spherical ; scutellum large ; abdomen 

 closely united to thorax, large and infiated. Antenna; two or three 

 jointed, with or without a terminal bristle or style, inserted high up 

 or low down. Eyes very large, contiguous in both sexes. Two, 

 three, or no ocelli i)re8ent. Proboscis rudimentary or very long. 

 Legs rather stout ; emj)odia developed pulvilliforni. Tegulae very 



