262 



DIPT ERA. 



ASILID.E. 



The Asilidfe resemble the TipuHdae in the general 

 shape of the body, but the thorax is somewhat short- 

 ened, and its posterior part is not wholly exposed. 

 If the abdomen is separated from the thorax on the 

 dorsal side, it will be seen that a part of the meta- 

 thorax fits into its basal portion as a ball fits into a 

 socket. These insects (Fig. 214) are rightly named 



robber-flies, insect- 

 hawks, and Missouri 

 bee-killers, for they 

 have the habit of 

 attacking bees, bee- 

 tles, dragon-flies,and 

 even other robber- 

 flies, sucking out the 

 soft parts of the 

 body and leaving 

 the chitinous skin. 

 This habit is corre- 

 lated with the follow- 

 ing peculiarities in 

 structure. The body is long (one species having a 

 length of two inches), and covered with stiff, brisding 

 hairs. The eyes are large and projecting, and the 

 black proboscis is powerfiil enough to severely sting 

 the hand of a man. The legs are armed with bris- 

 tles, and the wings are strong organs adapted for 

 swift flight. Many of the larvae are carnivorous like 

 the adults. Those living in the earth bore into the 

 grubs of beetles and devour them. They have a head 

 with two hook-like mouth parts. The pupae are free. 



Fig. 214. 



