69 



Some Lepidopterous Pupal Habitations and some 

 reminiscences. 



By Robert Adkin, F.E.S. Read Janiiori/ IWi, 1915. 



The life cycle of a lepidopteron consists of four distinct phases, 

 two of which are active, two quiescent. The most active stage is 

 that of the imago, during which the creature, by reason of its wings 

 and legs, is able to move about freely at will, and during its periods 

 of rest is in one way or another more or less protected from its 

 enemies. It is thus able to shift for itself. The imago lays its eggs, 

 and the egg-stage is of all four the most quiescent, and, therefore, 

 during its continuance, the organism is least able to escape any 

 attack of an enemy that may be made upon it ; but this is to 

 some extent compensated for, in some species by the positions 

 selected by the imago for depositing the eggs, or other circumstances, 

 or by the vast number of eggs produced (in some of the more 

 prolific species a single female will often lay as many as two 

 thousand eggs),^ and by all the laws of averages there is a good 

 prospect of some considerable proportion arriving at maturity. 

 Then follows the other active or larval stage, which is perhaps the 

 most important of the four, by reason that it is in this stage that 

 the insect attains its growth ; but it is also the most vulnerable. 

 This, however, is again to some extent compensated for by reason 

 of the creature having the power of free locomotion and conceal- 

 ment. The remaining stage is that of the pupa. In this the 

 creature, although not incapable of movement, has no power of 

 locomotion, and therefore must be regarded as quiescent. Now we 

 have already seen that the vast number of eggs produced may allow 

 of a considerable wastage without affecting the status of a species, 

 but by the time the pupal stage is reached the numbers may have 

 been so reduced by losses in the egg and larval stages, that unless 

 some protection is afforded to the pupa the result may be disastrous. 

 Many, varied and interesting are the means taken by the larva to 

 this end, in the construction of the home that is to protect the pupa 

 during tbe often lengthened period of its existence. 



These pupal habitations have from time to time attracted a good 

 deal of attention, first perhaps from a utilitarian rather than from 

 a scientific point of view. It is on record that some four thousand 

 to five thousand years ago the Chinese cultivated one or more 



1 " Camb. Nat. Hist.," vol. vi., p. 397. 



