49 



the older forms. (5) The great abundance of species in these 

 orders shows that metamorphosis is a great advantage to insects in 

 the struggle for existence. The period of exuviation is, in all 

 Arthropods, a very critical one, and they are at that time more than 

 usually helpless before the attacks of their enemies. The holometa- 

 bolous insects, by their power of storing up surplus food (fat-body) 

 in the larval stage, which they can use at leisure for their further 

 development in the pupal stage, by their power of hiding within 

 cocoons, &c., without the necessity of seeking food during this 

 critical period, are able to undergo the necessary changes in their 

 organisation with a minimum of exposure and risk. 



Metamorphosis, then, appears to be an adaptive habit which certain 

 insects have adopted in their struggle for existence against those 

 enemies by which they are everywhere surrounded, and against those 

 animals that compete against them for food. The habit of flying, by 

 which they are able to escape from numberless enemies that have 

 not this power, was probably one of the first factors in their develop- 

 ment that led to their ultimate success. The additional ability to 

 store up food in the early active (larval) stages of their existence, so 

 as to allow them to adopt a hiding habit and quiescent external form 

 at the most critical period of life, must, however, have been the 

 proximate cause of that success which has culminated in their being 

 numerically the most successful types of terrestrial life in existence, 

 the number of species being almost incredible. 

 . Gentlemen, I am afraid this is very bare and very meagre, — an 

 attempt, perhaps, to cover too much ground in a limited time ; still 

 I trust the time occupied will not have been altogether wasted. I 

 trust that I have been able to show you that there are branches of 

 entomology still rich in treasures for the worker, that there are views 

 of entomology beyond the destruction of our fauna, and that material 

 should be collected only for a definite scientific purpose and end, 

 and not accumulated to kill time, or because it will have a money 

 value some day. 



