WERNER MARCHAND 199 



of the series of combs on the anterior part of the last segment; this is 

 called by Neave the dorsolateral comb. It is not always present 

 and varies much in form. 



Preserving. — To preserve the larvae and pupae, for purposes of dis- 

 section, etc., our methods are still undeveloped. Harf^ (1895) says: 

 "The best results with most larvae of any size were obtained by 

 heating them in water, not too rapidly, to about 200° F., and setting 

 them aside till cool. A small percentage of acetic acid will prevent 

 the collapsing of very soft larvas." The principal trouble with this 

 method arises from the expansion of the air within, but a slight infla- 

 tion is sometimes desirable. This method is not suitable for pupas 

 generally, and Hart advises the use of 80 per cent alcohol and water 

 for their preservation. Experiments with formalin indicate that it 

 will satisfactorily preserve small and easily penetrable forms. 



Malloch (1917) has given further methods for preserving the larvse 

 and pupae. 



*i Hart (1895), pp. 159 and 160. 



