DIPT ERA. 



49 



four bristles, and the antennae generally terminate in a point which 

 appears to be rather a development than an appendage. 



This group includes a number of genera, but the following only 



Fig- 33.— Tabanus autumnalls. 



Fig. 34.— Chrysops csecutiens. 



possess sufficient interest to claim our attention. From the TcmystomcB 

 we select the families of the Asilidce, Empidce, and Boinbylidcs. 

 As types of the Bi-achystomcE we select the Leptidce and Syrphidce. 



The chief characteristic of the Asilidce is strength. All their 

 organs combine to produce this quality, which they display only 

 too much, being as formidable to cattle as the Tabani^ but even 

 surpassing those insects in natural cruelty. 



The Asilidce unceasingly attack other insects, and even those of 

 their own kind.. Their trunk is strong ; one of the fibres of the sucker 

 is furnished with small points, turned back, which are intended to 

 hold firmly to the body into which it has entered. They carry on 

 their devastations in the glades of woods and on sunny roads. 



