126 



ANIMALS OF LAND AND SEA 



and though most of them are not very speedy some, like the 

 robber-flies which feed on other insects, are by no means slow. 

 There are more different kinds of flight among the flies than 



among any other 



\ i^ C^ f^*'- <^0^£<^ kinds of insects, rang- 



ing from the direct, 

 swift and powerful 

 flight of the robber 

 and horse-flies and 

 the twisting and 

 dodging flight of the 

 lesser house-fly to the 

 dancing of the gnats 

 and the hovering and 

 darting of many syr- 

 phidsand bombyhids. 

 These last are com- 

 monly seen suspended 

 and apparently mo- 

 tionless in the air a 

 few feet above the 

 ground over woodland 

 paths; if startled they 

 dodge away so rap- 

 idly that frequently 

 the eye cannot fol- 

 low them. 



In most other in- 

 sects the four wings 

 when extended func- 

 tion as a single pair, 

 the hinder edge of 



the fore wings being hooked to the front edge of the hind wings 



in various ways, as in the butterflies, moths, bees, wasps, etc. 



In some of the butterflies and moths the wings are enormous 



in proportion to the size of the body. 



Figs. 284-298. Various Flies. 

 For explanations of the figures see p. xx. 



