HOW TO COLLECT, PRESERVE & STUDY INSECTS 233 



bucket of water; the dimg will sink, but after a little 

 while the beetles will crawl out and float on the surface 

 of the water when the}' can be caught easily. 



I have said that very little is up to now known about 

 the life histories of the Lepidoptera; this holds still more 

 force with the beetles. Few entomologists in South 

 Africa, if any, have given attention to this branch of 

 science, yet it is most interesting from many points of 

 view. The reason is perhaps the difliculty of rearing and 

 even obtaining the larvae of Coleoptera. However, the 

 student of Coleoptera should not lose a chance of study- 

 ing the life history of even the commonest species, and 

 what is more, of recording the observations in full. 



The Killing of Beetles. 



This is best done. I think, with the cyanide bottle, 

 though several workers use other methods such as: 

 dropping the beetles into alcohol, or steeping a tin filled 

 with them in hot water for half a minute or so. I do not 

 like to bring any insect in contact with alcohol, if it can 

 be avoided, as it often has an effect on the colouration of 

 the insect. Onh' dull coloured insects, such as black 

 and brown beetles might be treated thus without bad 

 results, but red and green are often changed very much 

 by alcohol. The brightness of the colour often disappears 

 even by a dry treatment but this is not due to the cyanide. 

 The hot water method is cumbersome, I think, as it neces- 

 sitates the carrying of Jiving beetles for some time, dur- 

 ing which they may injure themselves and each other. It 

 is true, that some beetles do not die readily in cyanide, 

 some indeed may live for a day even in a strong bottle, 

 but most of even those tenacious species will become 

 somewhat stupified within fifteen minutes and thus harm- 

 less to others. Though I found that most beetles do not 

 revive anymore after having been in a strong bottle for 

 an hour, yet I always left them in the bottle overnight. 



