1894-] ENTOMOLOGICAL NEWS. 245 



HINTS IN REGARD TO MOUNTING HYMENOPTERA 



AND DIPTERA. 



By W. A. NASON, Algonquin, 111. 



Dr. Henri DeSaussure, in his " Synopsis of Solitary Wasps," 

 published by the Smithsonian Institution, on page xix, makes 

 some interesting suggestions in regard to the preparations of 

 these insects for study. To observe to best advantage the char- 

 acters most useful in classification, they should, as he says, have 

 their wings drooped forward, leaving thus the meso- and meta- 

 thorax exposed, and in addition have the abdomen bent well 

 downward. 



The usefulness of some such system of preparation of most 

 Hymenoptera and Diptera has been impressed very strongly on 

 my attention recently. Groups differ much in the class of char- 

 acters most needed for study of the dorsal surface of the insects 

 above mentioned, but in nearly all the meso- and metathorax and 

 dorsal segments of abdomen, offer more or less characters of 

 importance. Many of the species of Diptera and Hymenoptera 

 fold their wings over the abdomen closely when killed. This 

 obscures the characters that should be most clearly exposed, 

 when assignment to families and genera is attempted. It also 

 makes the study of the venation, so important in these groups 

 troublesome, and often necessitates the softening process, and 

 possible mutilation of the specimen necessary. 



All this trouble the writer has found by experience to be easily 

 avoided by a few slight manoeuvres during the process of pinning. 

 It is my custom to pin with the insect held between forefinger 

 and thumb of left hand, and while the insect is still within the 

 grasp of the fingers, after the pin has transfixed the thorax, I 

 push up the wings to an angle of 45, more or less, thus exposing 

 the scutellum aad dorsal surface of abdomen. It also leaves the 

 wings in good position, for examination with the lens, to deter- 

 mine their venation. 



Where the above-mentioned plan fails to quickly accomplish 

 the desired position of wings I adopt another manoeuvre. While 

 the bee, fly, or other insect is still in process of mounting, I hold 

 the insect an inch or two from my mouth, with the transfixing 

 pin at an angle of about 45, with the vent of the insect toward 

 my mouth, and then blow the insect with greater or less force in 



