226 DIPTERA. 



measures nearly an inch in length. It is blackish above, and 

 reddish beneath and on the sides of the abdomen. The 

 species of Chrysops, Meig., are much smaller insects, about the 

 size of a common house-fly. They are black, with yellow mark- 

 ings on the abdomen, and the wings are black in the males, and 

 transparent, banded with black, in the female. They have 

 beautiful golden-green eyes, varied with purplish dots and lines. 

 But in spite of their beauty, these flies are among the most 

 troublesome of the family, frequently settling on the hand, and 

 making their presence known by a sharp puncture which draws 

 blood immediately. 



FAMILY XIX. Le-ptidce. 



Head short, flattened in front, often narrower than the thorax ; 

 antennae rather short, last joint rounded or conical, and furnished 

 with a terminal bristle; eyes contiguous, or nearly so, in the 

 male, and separated in the female ; ocelli present ; abdomen rather 

 long and narrow, or broad at the base, and gradually narrowed ; 

 legs long and slender, without bristles ; larvae and perfect insects 

 predatory, the former sometimes parasitic. 



The species of this family are rather slender, of moderate size, 

 and of dull colours, black, grey, or yellowish predominating. They 

 are frequently found at rest on tree-trunks, on the look-out for 

 prey. The larva of Termilio Degeerii, Macq., lives in sand, and 

 feeds on such insects as fall in its way ; those of the genus Leptis, 

 Fabr., are parasitic on cockchafers and other large beetles, and 

 those of Chrysopila, Macq., and Atherix, Meig., live in water. 



FAMILY XX. Asilidce. 



Head short and broad ; eyes prominent, separate ; ocelli 

 present ; antennae with third joint not annulated, with or without 

 a terminal bristle ; thorax narrowed in front into a slight neck ; 

 abdomen long ; legs moderately long, stout, and often hairy and 

 bristly ; larvae in damp earth ; perfect insects predatory. 



The Asilidce, or Eobber-Flies, are a family of considerable extent, 

 and include many large and conspicuous insects. They feed on other 

 insects, and are very courageous, sometimes attacking even dragon- 

 flies. One of our most conspicuous species is Asilus Crabroniformis, 

 Linn., which I have taken on the cliffs between Brighton and Rotting- 

 dean. It measures nearly an inch in length, and has a long taper- 



