SOUTH AFRICAN CATEUriLLAKS 185 



The straw or glass tube is then removed. A small piece 

 of wood is inserted and glued in, and the larval skin is 

 thus mounted by means of a pin stuck through the wood 

 behind the skin, or, the inserted straw having been re- 

 moved, the empty skin is glued to a cloth-covered piece 

 of wire, by means of the prolegs, and the end of this wire 

 is wound around a pin. 



But this method has the serious disadvantage that, at 

 least in most cases, the posterior part of the larval skin 

 is spoilt by being tied to the inflating tube and even- 

 tually being glued on the mounting straw or stick ; in 

 the other case, the prolegs are also all glued up by being 

 mounted on the wire. Some important parts of the larva 

 are thus rendered unfit for future examination. 



An improvement on this method was suggested to me 

 by Mr. Janse, and proved quite successful. This method, 

 with some change which our own experience taught us, 

 has given us results which compare very favourably with 

 the specimens of blown larvae prepared by the old 

 method. 



First, the caterpillar is left to starve for a day or more 

 in order to render the alimentary canal empty or prac- 

 tically so. The caterpillar is then killed in the cyanide 

 jar and left for from twelve to forty -eight hours, depend- 

 ing on its size. At the end of this period a certain 

 amount of decay has taken place which will be of assist- 

 ance in the following stage of the process. The larva 

 is now taken out of the cyanide bottle and put on a piece 

 of clean white blotting paper. Another piece of this 

 paper is put on top of it and gentle pressure applied, 

 starting behind the head of the larva and working 

 towards the posterior end. The intestinal wall having 

 partially decayed, tears loose somewhere in the thoracic 

 cavity, and is evaginated through the anal opening, 

 whence it protrudes. This is now cut off, a straw of suit- 

 able size inserted, and by means of a small pair of for- 

 ceps this alimentary tube is moved further and further 

 up along the straw until the latter reaches to the head 



