430 



THE STUDY OF INSECTS. 



long (Fig. 502). This family includes the larger members 

 of that series of flies in which the antennae are thread-like ; 

 but it also includes some species that are not larger than 

 certain mosquitoes. The most distinctive feature of crane- 

 flies is the presence of a transverse V-shaped suture on 

 the dorsal side of the mesothorax (Fig. 503). 



FIG. 503. Tho- 

 raxof acrane- 

 fly showing 

 the V-shaped 

 suture. 



FIG. 502. A crane-fly. 



The wings are long and narrow. In a few genera vein 

 III is five-branched, and the branches separate near the 

 middle of the wing (Fig. 504) ; but usually the number of 



vn, 



FIG. 504. Wing of Pratoplasa fitchii. (After Osten Sacken.) 



branches is reduced to three or four; and those that remain 

 distinct separate near the apex of the wing (Fig. 505). Cell 

 V 2 is divided into two parts by a cross-vein ; the branches of 

 vein VII like those of vein III separate near the distal end 

 of the wing ; and the margin of the wing is strengthened by 

 an ambient vein. 



