242 TRUE TALES OF THE INSECTS. 



these larvcc that, under favourable circumstances, pro- 

 duce imagines in September. The time of duration in 

 pupa thus varies exceedingly, from a few weeks, as in 

 the case just stated, to as many months, in the case of 

 the late pupae, whose appearance as perfect insects is 

 delayed until the following spring or summer. 



That we have but one generation of Atropos in the 

 year is generally understood. Yet it strikes one, that 

 larvse found full-fed as early as June must surely attain 

 the adult state before September. These larvie have 

 probably emerged from eggs laid by moths which on 

 occasions are seen here in May, and, it may be sug- 

 gested, they reach maturity by July or August, becoming 

 in their turn the progenitors of the late September and 

 October moths, and of the pupae whose development 

 remains in abeyance until the following year. Since 

 hybernated pupce in this country do not disclose the 

 moths until about June, in all probability these May 

 moths, the parents of the June larvce, are immigrants. 



On Rearino[ the Death's Head Moth. 



The pupse of Atropos, we have seen, are tender, 

 sensitive subjects, and most difficult to rear. Putting 

 things at their best, only about one in ten emerges. 

 Under natural conditions, by means of the large 



