88 THE CLASS OF INSECTS. 



either for purposes of study or tlie neat appearance of the col- 

 lection. 



Besides the vapor of ether, chloroform, and benzine, tlie 

 fumes of sulphur readily kill insects. Large specimens may 

 be killed by inserting a pin dipped in a strong solution of ox- 

 alic acid. An excellent collecting bottle is made by putting 

 into a Avide-mouth bottle two or three small pieces of cyanide 

 of i)otassium, which rna}^ be covered with cotton, about half- 

 filling the bottle. The cotton may be covered with paper 

 lightl}' attached to the glass and pierced with pin-holes ; this 

 keeps the insect from being lost in the bottle. For Diptera, 

 Loew recommends moistening the bottom of the collecting box 

 with creosote. This is excellent for small flies and moths, as the 

 mouth of the bottle can be placed over the insect Avhile at rest ; 

 the insect flies up into the bottle and is immediately' suffocated. 

 A bottle well prepared w^ll, according to Laboulbene, last 

 several months, even a year, and is vastl}' superior to the old 

 means of using ether or chloroform. He states, "the incon- 

 venience of taking small insects from a net is well known, as 

 the most valuable ones usually escape ; but bj' placing the end 

 of the net, filled with insects, in a wide-mouthed bottle, and 

 putting in the cork for a few minutes, thej' will be suffocated." 



Pinning Insects. The pin should be inserted through the 

 thorax of most insects. The Coleoptera, however, should be 

 pinned through the right wing-cover ; many Ilemiptera are 

 best pinned through the scutellum. The specimens should all 

 be pinned at an equal height, so that about one-fourth of the 

 pin should project above the insect. 



The best pins are those made in Berlin bj" Klager. Thej' are 

 of fiA-e sizes. No. 1 being the smallest; ISTos. 1, 2, and 5 are 

 the most convenient. For very minute insects still smaller pins 

 are made. A very good but too short pin is made by Edles- 

 ton and Williams, Crown Court, Cheapside, London. Their 

 Nos. 19 and 20 ma}^ be used to impale minute insects upon, 

 and then stuck through a bit of cork, or pith, tlu'ough which a 

 No. 5 Klager pin ma^' be thrust. Then the insect is kept out 

 of the reach of devouring insects. Still smaller pins are made 

 by cutting off' bits of ver}^ fine silvered wire at the right length, 

 which may be thrust by the forceps into a piece of pith, after 

 the insects have been impaled upon them. 



