268 ENTOMOLOGY. 



ning at the head, by means of a little glass roller, or even 

 a pencil or pen-handle; then, by rolling the caterpillar's 

 body, all the contents may be pressed out; this process 

 may be aided by drawing out the parts with fine pincers. 

 He also suggests that the empty skins of larvae, if placed 

 in alcohol of a strength of 48, may be sent by mail from 

 one country to another, or preserved for a few weeks and 

 then blown. Blown specimens need only to be protected 

 from the attacks of museum-pests and from dampness. 

 Small larvae, such as those of the Micros, may be put alive 

 into a hot bottle, baked until they swell to the proper ex- 

 tent and dry, when they can be pinned with all their con- 

 tents inside. 



Bleaching the Wings for the Study of the Venation. In 

 order to study the venation of the wings of butterflies and 

 the larger moths, we usually remove the scales with a stiff 

 camel 's-hair brush, and then the venation can be drawn 

 under a 2|- or 4-inch objective with the aid of the camera 

 lucida, and an exact sketch be made. Others prefer to 

 " bleach" the wings by caustic alkaline solutions. Dr. 

 Dimmock, however, suggests a modification of the chlorine 

 bleaching process, commonly employed in cotton bleacher- 

 ies. After soaking the wings for a few moments in pure 

 alcohol, in order to dissolve the oily matter in them, they 

 can be removed to a solution of common bleaching-powder, 

 which is sold as "chloride of lime/' but which is really a mix- 

 ture of calcic hypochlorite, calcic chloride, and calcic hy- 

 drate. Ten parts of water dissolve the first two compounds, 

 leaving nearly all the third suspended in the solution, which 

 should be made with cold water, filtered, and kept in a 

 tightly-corked bottle till required for use. After the color 

 has sufficiently disappeared from the wings, they should be 

 transferred to a wash composed of one part of strong hy- 

 drochloric acid to ten parts of water. The wings may then 

 be gummed on cards, or upon glass by the proper transfers 

 through alcohol and chloroform to Canada balsam. 



A solution of sodic hypochlorite, known as eau de La- 



