MOTIONS OF INSECTS. ,361 



winglets are largest in the heaviest bodies, and alto- 

 gether wanting in the lightest — that one of their prin- 

 cipal uses is to assist the wings when the insect is flying. 



The flight of the Tipulidan genera is very various. 

 Sometimes, as I have observed, they fly up and down 

 with a zig-zag course; at others in vertical curves of 

 small diameter, like some birds ; at others, again, in hori- 

 zontal curves : — all these lines they describe with a kind 

 of skipping motion. Sometimes they would seem to flit 

 in every possible way — upwards, downwards, athwart, 

 obliquely, and sometimes almost in circles. The common 

 . gnat {Culex pipiens) seems to sail along also in various 

 directions. The motion of its wings, if it does not fly 

 like a hawk, is so rapid as not to be perceptible. When 

 the crane-fly {Tipula oleracea) is upon the wing, its 

 fore-legs are placed horizontally, pointing forwards, 

 and the four hind ones stretched out in an opposite 

 direction, the one forming the prow, and the other the 

 stern of the vessel, in its voyage through the ocean of 

 air. The legs of another insect of this tribe {Hirtcea 

 Marci) all point towards the anus in flight, the long 

 anterior pair forming an acute angle with the body : — 

 thus, perhaps, it can better cut the air. 



I have often been amused in my walks with the mo- 

 tions of the hornet-fly (Asilus crabroniformis, L.), be- 

 longing to the second division just mentioned. This 

 insect is carnivorous, living upon small flies. When 

 you are taking your rambles, you may often observe it 

 alight just before you ; — as soon as you come up, it flies 

 a little further, and will thus be your avant-courier for 

 the whole length of a long field. This usually takes 

 place, I seem to have observed, when a path lies under 



