286 ENTOMOLOGY. 



the thorax, preferably with japanned iron pins.* They 

 should be placed on the pin only low enough so that the 

 head may be grasped with the thumb and forefinger without 

 danger to the specimen. The wings should never be 

 spread. Spreading not only renders the specimens more 

 difficult to study, but it spoils the natural appearance of 

 the insects, and is a positive injury to them for the cabinet. 

 All that is necessary is to push aside the wings so that they 

 will not conceal the abdomen. Minute specimens should 

 be pinned with fine iron wire from the under side, and then 

 pinned upon small strips of thin cork, the upper surface of 

 which has been covered with white paper, and through the 

 other end of which a pin is thrust. Small specimens should 

 never be glued to bits of cardboard, as is commonly done 

 with Coleoptera. Only one specimen should be placed on 

 the piece of cork. 



" The greatest enemy to dipterological collections is dust: 

 insects can be guarded against, but it is difficult to exclude 

 dust, unless tight cases are used. Dampness and mildew 

 do often much mischief. 



" A good dipterological specimen must be unrubbed, un- 

 moistened, not dusty nor greasy, and with the wings un- 

 spread. It is quite as easy to collect good specimens as 

 poor ones, and much more satisfactory/' (Psyche, iv. 138.) 



Dr. Williston writes me that for the collection of Bom- 

 bylidae and similar hairy flies " my present custom is to 

 pin the fly while in the net, without directly touching it, 

 and then to remove it, and either kill it in the cyanide 

 bottlef or with a match, then pinning it in a box. The 

 specific characters of many Bombylids are in the hairs, 

 which are very easily rubbed off. It is almost impossible 

 to collect them in a bottle and get good specimens." 



In an elaborate paper J. Mik, the Austrian dipterist, 



* Dr. Williston writes me that he does not like japanned pins so 

 much as formerly, as they bend so easily, 

 f Dr. Williston prefers 1-oz. cyanide bottles. 



