47° THE STUDY OF INSECTS. 



VII, coalesces with vein V s , as shown in the figure; but 

 in the males the tip of vein YII, is free. The posterior 

 lobe is wanting. 



Three ocelli are present. The antennae are three-jointed ; 

 the third segment is globular, and bears a three-jointed 

 style. 



These flies are common from spring till autumn, in damp 

 grassy places. They frequent the shores of shady brooks, 

 where the atmosphere is moist. But little is known as yet 

 about their habits and tranformations. 



In the shape of the wings, the absence of cross-veins, 

 except at the base of the wing, and the great reduction of 

 the anal area of the wing the flies closely resemble the Psy- 

 chodidae. 



Suborder CYCLORRHAPHA (Cy-clor'rha-pha). 

 The Circular-seamed Flies. 

 To this suborder belong those families of flies in which 

 the pupa escapes from the larval skin through a 

 round opening made by pushing off the head- 

 end of it (Fig. 573). The pupa is always enclosed 

 in a puparium. The adult flies possess a frontal 

 lunule (see footnote page 461), and except in the 



Pu' G arfum~of ^ rs ^ ^ our f am ' nes a frontal suture, through which 

 a Muscid. t j ie ptilinum is pushed out, when the adult is 

 about to emerge from the puparium (see page 419). 



Family Syrphid^E (Syr'phi-dse). 

 The Syrphus- flies. 



The family Syrphidse includes many of our common 

 flies; but the different species vary so much in form that 

 no general description of their appearance can be given. 

 Many of them mimic hymenopterous insects ; thus some 

 species resemble bumblebees, others the honey-bee, and 

 still others wasps; while some present but little resemblance 

 to any of these. 



