ENTOMOLOGY. 77 



either heat or cold, none having ever been found pro- 

 ductive after remaining for a time in the vacuum of 

 an air-pump. 



When the whole of the fluid in the interior of the 

 egg has "been assimilated, and the young larva ma- 

 tured, it emerges either by rupturing the envelope, 

 gnawing it asunder, or pushing open a kind of move- 

 able lid at the end, constructed apparently for the 

 express purpose of facilitating its exit. 



Larva. Insects as often present themselves to 

 our notice in this stage of their existence as in their 

 perfect state, and not unfrequently attract our atten- 

 tion by their depredations on the produce of our 

 fields and gardens. In consequence of being so 

 familiarly known, they are distinguished by a variety 

 of popular names. Grubs are the larvae of coleop- 

 tera ; maggots, mawks, and gentles, those of diptera ; 

 and caterpillars the larvae of butterflies, moths and 

 saw-flies : the larvae of most of the other races not 

 differing materially in appearance from the matured 

 insects, do not require a distinctive appellation in or- 

 dinary language. Lepidopterous larvae, or the cater- 

 pillars of butterflies and moths, we have already de- 

 scribed at considerable length ; * those of beetles also 

 have been occasionally noticed,! and the particular 

 history of the other kinds will be afterwards given 

 under their respective orders and families. The pre- 



* See Naturalist's Library Entomology, British But- 

 terflies. 



t See Naturalist's Library Entomology, Beetles. 



