DIPTERA. 485 



suction. Their larvae have a small squamous head, armed with two mova- 

 ble hooks, live in the earth, and there become nymphs, whose thorax is 

 furnished with dentated hooks, and the abdomen with small spines. 



EMPIS, Lin. 



Closely allied to Asilus in the form of the body and the position of the 

 wings, but with the proboscis perpendicular or directed backwards. The 

 head is rounded and almost globular; the eyes very large. 



These Insects are small and live on prey and the nectar of flowers. The 

 last joint of their antennae is always terminated by a biarticulated or short 

 stilet, or by a seta. 



The remaining Tanystoma of our first division usually have a short, wide 

 body, the head applied directly to the thorax, the wings distant and the 

 abdomen triangular. In a word, their general appearance is that of our 

 domestic Fly. Their proboscis is frequently long. 



CYRTUS, Lat. 



Intermediate between Empis and Bombylius. The wings are inclined on 

 each side of the body; and the alulse very large and covering the halteres; 

 the head is small and globular, the thorax very high or gibbous, the abdo- 

 men vesicular and rounded, or almost cubical; the antennae are closely ap- 

 proximated, and the proboscis is directed backwards or wanting. 



BOMBYLIUS, Lin. Bombyliers, Lat. 



Where the wings are extended horizontally on each side of the body, and 

 the halteres are exposed. The thorax is higher than the bead, or gibbous 

 as in Cyrtus; the antennae are closely approximated, and the abdomen is 

 triangular or conical; the proboscis is directed forwards. The proboscis is 

 generally very long and most slender at the extremity. Their legs are long 

 and attenuated. They fly with great velocity, hover over flowers without 

 alighting on them, introduce their trunk into their calyx to obtain their 

 nectar, and produce a sharp humming sound. 



ANTHRAX, Scop. Fab. 



Similar to Bombylius; but where the body is depressed, or but slightly ele- 

 vated and not gibbous, with the head as high and as broad as itself. The 

 antennae are always short, and distinct from each other, and always termin- 

 ated by a subulate or punch-like joint. The proboscis, except in a small 

 number, is generally short, extending but little beyond the head, frequently 

 even withdrawn into its oral cavity, and terminated by a little inflation 

 formed by the lips. The palpi are usually concealed, small, filiform, and 

 each, at least in several, adhering to one of the threads of the sucker. The 

 abdomen is less triangular than that of the Bombylii, and partly square. 

 These Insects are generally hairy. Their habits are very analogous to 



