( Iviii ) 



my collection would be practically complete in all but micro- 

 scopic forms. 



" Since I started this letter, I have added considerably to 

 the collections of minute Hymenoptera and Diptera ; the 

 former especially seem to be exceedingly numerous ; this is 

 in accordance with what I have always said, that the Hymen- 

 optera in the tropics are more numerous than the Coleoptera. 

 Mr. Smith, my assistant, is doing very nicely in these minute 

 things, and has already learned to set the little flies quite 

 well. He wishes to go to Barbadoes about Christmas, and I 

 propose to keep him there for two or three weeks collecting 

 flies and spiders. I do not fancy that that island will repay 

 much work, as the forest with which it was originally covered 

 has all been cut away. 



" A word about my setting of minute insects. I am 

 quite satisfied with the method of mounting the small 

 Diptera, as it is neat, secure, and puts them in good 

 shape for study ; but I am not so well satisfied with the 

 little Hymenoptera ; I mean the most minute ones, which 

 are so tiny and hard that I cannot put them even on 

 the point of a fine pin. I gum them to the points, and 

 they look very well, only now and then I cannot get 

 the wings free from the abdomen ; still in a series of 

 specimens there will hardly be any species in which the 

 abdomen is concealed in this way. The real points of doubt 

 are — (1) Will the minute portion of gum used be permanent, 

 so that there will be no danger of the specimens falling off ? 

 (2) Will it not eventually corrode the point of the pin ? The 

 gum used is composed of sugar, tragacanth, and gum arable ; 

 this I have found very permanent, having used it for ten 

 years ; and it sticks to the pin-points quite as well as to cards ; 

 I have thoroughly tested the specimens, and, when properly 

 put on, they seem perfectly secure. I can think of no other 

 method, except gumming them to cards, and it is impossible 

 to do this without more or less daubing the wings and legs ; 

 besides, it takes much longer, and they are generally less 

 secure in the end than by my method. I can use shellac for 

 gumming them, but they cannot then be taken off the pin. 

 Also I can use platinum wire for mounting them, as I have 



