markings and attitudes of lepidopterous larva. 317 



species includes a very great difference in size between 

 the^ imagines of the two broods, as well as a most 

 decided divergence in colour. 



The dates of the various events of the life-history 

 during the present year (1884) have been as follows : — 

 The ova were laid April 14th and 15th; the larvae 

 hatched from May 2nd to the 11th ; the first larvae spun 

 up June 1st, the others at various subsequent dates all 

 through June and into July. I conducted experiments 

 with artificially induced cold upon most of the pupae, 

 but the imagines emerged a few days after the with- 

 drawal of the ice in all cases. A few pupae were not 

 exposed to cold, and these had pupated towards the 

 beginning of July, emerging in about twelve days. The 

 eggs of the next brood were laid on July 4th, and a few 

 days afterwards, by a moth which had been exposed to 

 ice in the pupal state for thirteen days. (The male 

 wliich fertilised the eggs had been similarly exposed for 

 nine days). The tendency of this cold would, of course, 

 be towards diminishing the number of broods in the 

 year, and, as it did not have this effect, it may be left 

 out of consideration, except as keeping back all sub- 

 sequent events by a period about equal to that passed 

 in the cold. The eggs hatched in the middle of July, 

 and the larvae spun up from the 20th of August to the 

 middle of September. One, however, only spun up on 

 October 29th. The perfect insects emerged in from two 

 to three weeks, but a considerable jn'oportion have not 

 emerged and constitute the winter brood. Eggs for a 

 third brood were laid September 15th and the following 

 days, turning brown in two or three days, as on previous 

 occasions. The larvae began to hatch on October 4th. 

 These larvae are not adult at the present date (December 

 18th). They have been partially kept back by the 

 difficulty of obtaining food at this time of the year, but 

 there is great doubt as to whether they could have lived 

 at all in the open air, unless, indeed, these larvae hyber- 

 nate. Thus there have been three broods of larvae this 

 year, and some individuals of the first brood showed 

 tendencies towards a winter pupation (but died as larva) ; 

 many individuals of the second brood are passing the 

 winter as pupae, and it seems hkely that the third brood 

 will hybernate as larvae. 



Summary. — There are a few especially interesting 

 features in this ontogeny. The two first stages are 



