SOUTH AFRICAN CATERPILLARS 183 



its caterpillar may not have been known. In the process 

 of rearing through we have obtained the adult, but we 

 shall probably not remember the larva. Thus science has 

 not been advanced, and we are as far as we were before 

 in regard to the species. 



The first specimen of a larva should be preserved; the 

 next reared to the pupa stage and this preserved, and 

 only after Ave know these two stages should further cater- 

 pillars be carried through to the adult stage. Of course, 

 in the majority of cases, there will be sufficient material 

 collected to allow both larva and pupa to be kept and the 

 adult to be reared, but uncommon caterpillars, which are 

 only occasionally met Avith in small numbers, should be 

 treated as I have indicated. 



The first thing to do is to make a recognisable descrip- 

 tion of the colour and markings of the caterpillar, as it 

 must be remembered that in the majority of cases these 

 colours Avill disappear or change in the process of preser- 

 vation. 



The caterpillars should be preserved both for subse- 

 quent study and for display in the cabinet. 



Preservatiox of Larvae for Study. 



The preserving fluids used most commonly for this pur- 

 pose are alcohol, formalin or alcohol plus glycerine in 

 equal parts. The first is to be preferred. Formalin is 

 said to preserve the natural colours to a certain extent, 

 but we have found its assistance in this matter very 

 slight. It has, moreover, the disadvantage of being dis- 

 agreeable to handle and of making the specimens too 

 brittle for future study. Alcohol-and-glycerine mixture 

 has the advantage that, if the alcohol evaporates — the 

 cork is not always close fitting- — the specimen will not 

 dry out. but will remain moist through the hygroscopic 

 qualities of the glycerine it contains. But it has this dis- 

 advantage, that, if the specimen be used later for dissec- 

 tion and the mounting of parts as permanent microscop- 



