51 



On a Method of Mounting Whole Insects Without 

 Pressure for the Binocular Microscope. 



By Staniforth Green. 



(Communicated by Mr. T. Curties ; Read March 22, 1878.) 



Minute Hymenoptera (Iclineumonidse, Chalcididae, Proctotrupida?, 

 &c), require little manipulation to render them fit for mounting in 

 Canada balsam, and they are easily collected. I have captured 

 numerous species in Ceylon by sweeping the grass with a small bag 

 net, about Sin. in diameter at mouth, and tapering down to a point 

 at bottom. It should be made of fine cambric, as many of these 

 small insects do not exceed the ^ ¥ of an inch in length. About a 

 dessert-spoonful of spirit of turpentine should be placed in an ordi- 

 nary wine glass, over which the net is to be drawn after a sweeping 

 operation. While this is being done, the captured insects must be 

 confined to the bottom of the net by gathering the net between the 

 thumb and finger at about one inch from its bottom. When it has 

 been drawn over the glass as far as it will go, then the thumb and 

 finger must be removed, and the insects allowed to fall into the 

 turpentine. They will quickly die, mostly with outspread wings and 

 legs. Minute species should be fit for mounting after they have 

 remained in turpentine for a few days. This treatment, however, 

 will not succeed with more horny kinds, which, when thrown into 

 turpentine or spirits of wine, curl themselves up in dying, and can- 

 not afterwards be straightened out. Insects of that class should be 

 placed alive on a piece of glass, and while walking, a thin covering 

 glass can be let down upon them. Strong sj^irits of wine must be 

 quickly introduced between the two glasses by means of a camel's- 

 hair brush. This soon kills the insect in the position of walking, and 

 it should be kept so in spirits for at least six hours. I use the ordi- 

 nary 3x1 inch slip and a good sized covering glass — the heavier 

 the better. Seven or eight sjDecimens can be so arranged on one 

 slide, which may be placed in a saucer containing sufficient spirits of 

 wine just to cover them. They can afterwards be transferred to 

 turpentine to render them fit for mounting in Canada balsam. 



