r'jQ2. on caterpillars. 289 



cipal divisions which are produced from the eggs c*^ 

 insects, each of which admit a great number of 

 lefser varieties. These are caterpillars, grubs, and 

 maggots. Nor is the interposition of providence 

 more conspicuously apparent in any one instance, 

 than in that unerring' instinct that directs the pa- 

 rent fly to deposit its eggs upon such substances as 

 are fitted to afford proper food for tlie young, 

 as soon as they fhall be produced. In general cater- 

 pillars are deposited on plants, grubs in the earth, 

 and maggots in animal substances. 



But though this rule be general, it is not univer- 

 sal. The gall insects, whose eggs produce a species 

 of maggot, are always deposited on plants peculiar to 

 each species. And though I do not at present re- 

 collect any animal of the caterpillar tribe that lives 

 on animal substances, yet it is by no means impof- 

 sible but there may be some of that kind. Whether 

 the animals that ifsued from the body of these ca- 

 terpillars were of this sort, or to what other 

 clafs of reptiles they belong, remains to be as- 

 certained. That they could not be the young of 

 the caterpillar itself from which they ifsued, seems 

 to be undeniable ; as this would be a mode of pro- 

 creation totally different from what is known to talce 

 place among that tribe of animals. From the obser- 

 vations of my correspondent, indeed, ■ it does not 

 seern to be of the caterpillar genus at all, as it wants 

 •feet • nor is the cocoon of the nature of that produ. 

 ced by caterpillars in general ; for these are always 

 made to envelope a chrysalis for a- time ; whereas, 

 upon examining some of the small cocoons here al- 

 luded to, there is not the smallest appearance of a 

 VOL. xi. 0,0 t 



