INSTRUCTIONS FOE COLLECTING INSECTS. 1G9 



not require raucli care ; only do not let the place in which, they are 

 kept be too warm. Those I wish to separate are put in large glass 

 jars, the tops of which are covered with paper. The others I place in 

 a wooden box, which I keep in an unheated room, on the window-sill. 

 AVhen they are developed from the pupa towards spring, they natu- 

 rally fly to the window, from which I take them with a glass vial, or, 

 what is better, with a small chip-box furnished with a glass bottom. 



The third point of great importance is the preparation and pinning 

 of the specimens for the cabinet. Sulphuric ether and chloroform are 

 but inferior means of killing them. Specimens too long exposed to 

 these agents are apt to spoil, and, if too little exposed to them, they 

 revive. They answer only for certain tender minute species, of which 

 I shall speak below. The best means of killing them are kreosote and 

 the smoke of a strong cigar. The general rule is, to pin the flies 

 whilst living, and thus to put them into the collecting box, which, 

 should have the bottom well moistened with kreosote, and be made 

 tight. The captives will soon die, and thus, time after time, fresh 

 subjects may be put in as they are caught. I have had boxes in which 

 the largest Diptera were almost immediately killed, although the kreo- 

 sote had not been renewed for six days, and which were still fatal to 

 smaller species for six months afterwards. If you have no boxes thus 

 prepared with kreosote, or, if you wish to avoid the odor of it, then 

 prepare a box, so that, when it is full of pinned specimens, you may 

 blow a few strong puffs of cigar-smoke into it, and all life will soon 

 cease. 



In the pinning of specimens, the long pins are greatly to be ^'s- -• 

 preferred to the short ones. Five-sixths of all the entomolo- ®' 

 gists now use the long pins, m n, fig. 2, is the normal length 1 d 

 of pins v/hich are used for Diptera ; the finer kinds may be of \7) 

 the length m d. The insects must be pushed high enough up 

 the pin to enable the surface of its back to be examined with an 

 ordinary lens witliout being incommoded by the pin's head. 

 The back of the insect must, of course, be a little nearer the 

 pin's head than the length of the focus of the glass. As smaller 

 insects must be examined by glasses of higher power, they must 

 be brought nearer the pin's head than larger ones. 



Large flies may be pushed up so that their backs come to h, <^ ' 

 which smaller ones should reach a. Since the beautiful magni- 

 fiers of Oberhauser, which allow the application of a lower power, 

 have come into use, insects may be pinned at a greater distance from 

 the head, but not much greater. 



The minute and tender species, such as the smallest Cecldomyke, 

 Campy lomjza', and others, must be treated difierently. They cannot 

 be pinned in the ordinary way with safety. Van Heyden has pro- 

 posed the most rational and elegant method. The smaller species are 

 caught by the linen bag, and are then put into very porous chip pill 

 boxes, and are killed with cigar smoke, if boxes moistened with 

 kreosote are not preferred. When twenty or thirty are captured the 

 box is turned up so that specimens fall into the cover. They are then 

 transfixed from below on fine silver wire, but not so as to allow the 

 wire to project beyond the thorax. The silver wire must previously 



