DIPTERA. 455 



The larger species, as well as some of moderate size, 

 belong to the genus Tabanus (Ta-ba'nus), of which nearly 

 one hundred American spe- 

 cies are known. One of the 

 most common of these is the 

 Mourning Horse-fly, Tabanus 

 atratus (T. a-tra'tus). This 

 insect is of an uniform black 

 color throughout, except that 

 the body may have a bluish 

 tinge (Fig. 540). 



To the genus Chrysops FlG ' **££"" "'" F q^£ST 



(Chry'sops) belong the smaller niger ' 



and more common horse-flies with banded wings (Fig. 541). 

 Nearly fifty North American species of this genus have 

 been described. 



Family Stratiomyiid^ (Strat-i-o-my-i'i-dae). 

 The Soldier-flies. 

 The soldier-flies are so called on account of the bright- 

 colored stripes with which some of the species are marked. 



In the more typical mem- 

 bers of this family the abdo- 

 #\ men is broad and greatly 



BI I flattened (Fig. 542), and the 



Wj \ wings when at rest lie parallel 



w j0mL upon each other over the ab- 



18 WmiS domen. But in some genera 



l\ %~j^ th e abdomen is narrow and 



Fig. 542. v ^ \J -,iii 



stratio- considerably elongate. 



myia. FlG s Fig. 544. „,. . ., 



The antennae vary greatly 

 in form ; in some genera the third segment is long and con- 

 sists of several quite distinct rings (Fig. 543) ; in others it is 

 short with but few indistinctly-separated rings and with a 

 bristle (Fig. 544), as in the true true short-horned flies. 



The most distinctive characteristic is the peculiar vena 



