80 THE ENTOMOLOGISt. 



various diameters, so that the largest or most minute larvge 

 may be operated upon. Two pieces of watch-spring, about 

 three inches long, each having a portion at the lip heated, 

 and then bent at right angles, a quarter of an inch from the 

 end, should be bound round the blowpipe, as shown in 

 fig. 1. A spirit-lamp, tripod stand, and an oven, are also 

 requisite, the latter — represented in the sketch by the glass- 

 bottle, as shown in fig. 2 — being easily made from a tin- 

 canister, such as chocolate is generally sold in, by punching 

 out of the lid a hole the size of a florin. 



It is almost superfluous to mention that the larvae should 

 be in good condition, and selected, if possible, shortly after 

 their skins are cast, but not before they have regained their 

 toughness. They should be killed in the cyanide bottle, or 

 with anything not destructive to their colour, and then 

 steeped for an hour or so in a solution of alum to harden the 

 skin. The internal organs are then to be removed by 

 forcing them through the anal aperture with the fore finger 

 and thumb between blotting-paper. The inside being com- 

 pletely removed in this way, the larva should be fastened to 

 the blowpipe in such a manner that the two pieces of watch- 

 spring pressing against the point of the tube may grasp the 

 smallest portion of its last segment. Thus fastened, it can be 

 gently inflated and kept distended whilst drying in the oven, 

 which, in the case of small specimens, will occupy from one 

 and a half to two minutes, according to the heat, which 

 should not be raised very high for those of a delicate colour. 

 It sometimes happens that when inflated the larva does not 

 assume the position required: it bends into a semicircular 

 form, or the head-part curves downwards. To remedy this a 

 simple arrangement of thin wire tied to the blowpipe, as 

 shown in fig. 3, may be made to hold it whilst drying; in 

 fact, by bending the wire it may be held in any position. 



mA/rr 



Fig. 3. — Fine wire attached to blowpipe to hold lavvK whilst drying. 



When removed from the oven dry, the specimens are ready 

 to be mounted' on twigs, very fine ones being cut to fit in 



