52 



BULLETIN 67, UNITED STATES NATIONAL MUSEUM. 



Fig. 94.— A bot- 

 tle WITH TUBE 

 THROUGH THE 

 STOPPER. 



a goose quill with the outer end cut obliquely (fig. 94) . The minute 



insects may be scooped up with the end of the quill and fall through 



it into the bottle. If the cyanide jar is well made, most insects 



will die in a few moments. Those with bright yellow 



colors should not be left in any longer than necessary, 



as the cyanide vapor turns the yellow red. 



All delicate insects and those with fragile legs should 

 be pinned as soon after their death as possible. Too 

 much importance can not be placed on this matter, as 

 delicate insects are rarely properly prepared, and the 

 main difficulty is that they have been left too long in 

 the poison bottle. Therefore, after one has collected a 

 while, he should sit down in some shady nook and pin 

 the more fragile species. Most insects, however, may 

 remain in the bottle for four or five hours. 



Various other poisons have been used to kill in- 

 sects. English entomologists advocated the use of 

 crushed laurel leaves. These, however, have not a 

 very strong odor. Others prick the insect with a 

 needle or pin dipped in a saturated solution of oxalic acid, after 

 being quieted with chloroform. Many entomologists have used 

 chloroform or ether to kill insects. Chloroform, however, is apt 

 to stiffen the muscles of insects, so that it is not easy to spread 

 their wings. When insects are collected in pill 

 boxes, a drop of chloroform on the cover will 

 soak through and kill the insect inside. Some 

 take into the field a bottle of chloroform (fig. 95), 

 with a brush attached to the stopper. Touching 

 the side of the thorax of the insect with a moist 

 brush will be sufficient to quiet it. Chloroform is 

 so volatile that if enough is not used at first to 

 kill the insect it will soon revive and damage itself 

 in its struggles. 



Chloroform may be used to advantage in collect- 

 ing small insects that are very active in flight, par- 

 ticularly when they rest on the under surface of 

 leaves. A wad of cotton is placed in the bottom 

 of a tube, a few drops of chloroform poured upon 

 it, and then a piece of blotting paper and some 

 fine strips of loose paper placed over the cotton. 

 The tube is brought stealthily up under the insect 

 which, instantly overcome by the strong chloro- 

 form vapor, drops into the tube. Thus, one after another may be 

 taken in rapid succession. Such tubes will last only a day or two. 

 A piece of rubber soaked in chloroform will retain the odor for a 

 long time. If the insects are to be pinned, it should be done shortly 

 after they are dead, else they will be too stiff and dry. 



F|IG. 95.— A CHLOROFORM 

 BOTTLE WITH BRUSH. 



