CHAP. XXII. HOW TO COLLECT AND PRESERVE INSECTS. 143 



their way into the body of their victim ; here they remain 

 until reaching their full growth, when they gnaw their way 

 out and drop to the ground, which they enter and form 

 smooth cells; they do not cast their skins before changing to 

 pupae, but their skins contract and harden, thus supplying the 

 place of a cocoon. At the proper time the perfect fly (Fig. 236) 

 issues, and makes its way to the urface of the earth. This 

 fly very closely resembles the common House-fly, but may at 

 once be distinguished by this, that the slender bristle on the 

 last joint of the antenna is naked, whereas in the House-fly 

 this bristle is pectinate, like a feather. 



CHAPTER XXII. 



HOW TO COLLECT AND PRESERVE INSECTS. 



A cabinet of some kind is almost indispensable to the 

 student of Entomology; in it he should place as many different 

 species of insects as he is able gradually to obtain, both by 

 collecting and by exchanging duplicate specimens with friends. 



One of the chief requisites for successful collecting is a net. 

 The accompanying figure (Fig. 335) illustrates the frame work 

 of a very convenient net, such as used by Professor Riley, and 

 its construction is thus described by him: "Take two pieces 

 of stout brass wire, each about twenty inches long; bend them 

 half circularly and join at one end by a folding hinge having a 

 check ( b ) on one side. The other ends are bent and beaten 

 into two square sockets (/) which fit to a nut sunk and 

 soldered into one end of a brass tube ( d ). When so fitted 

 they are secured by a large-headed screw (e) threaded to fit 

 into the nut-socket, and with a groove wide enough to receive 

 the back of a common knife blade. The wire hoop is easily 

 detached and folded, as at c, for convenient carriage ; and the 

 handle may be made of any desired length by cutting a stick 

 and fitting it into the hollow tube (a), which should be about 

 six inches long." 



