MOTIONS OF INSECTS. 361 
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 (Hirte@a 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 motions 
of the hornet-fly (Aszlus crabroniformis, L.), belonging to 
the second division just mentioned. This insect is car- 
nivorous, 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 ob- 
served, when a path lies under a hedge; and perhaps the 
object of this manceuvre may be the capture of prey. 
Your motions may drive a number of insects before you, 
and so be instrumental in supplying it with ameal. Other 
species of the genus have the same habit. 
The aérial progress of the fly tribes (Muscide), includ- 
ing the gad-flies (@istrus) ; horse-flies (Tabanus); carrion- 
flies (Musca), and many other genera—which constitute 
the heavy horse amongst our two-winged fliers—is won- 
derfully rapid, and usually in a direct line. An anony- 
mous observer in Nicholson’s Journal* calculates that, in 
4 Ato, 111, 36. 
