178 BRITISH LEPIDOPTERA. 



the moths were on flight and ovipositing some time before Williams 

 and Oswald obtained their specimens (all 2 s except one). This 

 view is strongly supported by Cooper's statement (Ent., xxi., p. 

 257) that, at Shoeburyness, during the last week of August, he 

 found the larvae commonly, and that their traces hinted that they 

 had been in great numbers, and that many had already pupated. 

 Meek also records having taken 150 larvae at Kingsdown before 

 the end of August, and Greasley had fullfed larvae on August 28th, 

 and one would suppose that the bulk of the earliest eggs were laid all 

 over those parts of Britain where the species occurred, by the middle 

 of July. Such evidence as there is goes to support the suggestion 

 that there is occasionally a flight of immigrant imagines into this 

 country in July or August, that a comparatively few of these are captured 

 in the ordinary way by collectors, that these immigrants find plenty 

 of suitable spots in which to oviposit, that our summer is suitable 

 to the growth of the early larvae, but that our autumn is quite 

 unsuitable both to larvae and pupae, that the late autumnal larvae 

 are killed off, and that the pupae resulting from the earlier ones are 

 unable to pass through our winter successfully in a state of nature. 

 Want of sun would appear to be the greatest enemy to their con- 

 tinued existence in this country, certainly the mere low temperature 

 of our winter is insufficient to explain their failure to acclimate them- 

 selves, if one considers fairly the winter temperature of some of 

 their permanent localities in the Alps of Central Europe. That 

 pupae go over for many years, and then, as a result of unexplained 

 and unknown causes, produce imagines in great numbers at irregularly 

 recurrent long distances of time, is not worthy of consideration by 

 scientific men, and has no atom of evidence in its support. As 

 bearing on the meteorological difficulties the larvae have to meet 

 here, Hele observes that some 150 larvae were obtained by 

 himself and two friends at Aldeburgh in the autumn of 1888, and 

 that, in the early part of October, when there were some frosty 

 mornings, the mortality among them became great. Chappell notes 

 ( Young Nat., ix., p. 238) that he found several dead larvae at 

 Blackpool in the autumn of 1888. Tugwell observes ( Young Nat., x., 

 p. 44) that many of the apparently healthy larvae that he obtained in 

 1888 died half-changed, and believes that the early cold of September 

 paralysed them completely ; he suggests that our early cold and wet 

 autumns kill off wild larvae. Arkle records (Ent., xxi., p. 257) some- 

 what similar observations, and states that he came across many dead 

 and dying larvae when searching at Wallasey. No doubt climatic 

 conditions are among the chief factors in preventing this species from 

 obtaining a permanent footing in these islands. As to rearing the 

 larvae in confinement, Newstead notes that 21 were successfully reared 

 in a strong box provided with a strong gauze covering and three parts 

 filled with dry sand. They were supplied twice daily with fresh, 

 " hard " food ; the box was so placed as to catch all the rays of the 

 sun, but was always put under shelter at night and also in wet weather; 

 the larvae seemed to revel in the hot sunshine, but became more or 

 less torpid in wet cold weather and at the approach of night. 



Larva. — First ///star (July 17th, 1901): Of medium thickness, 

 evenly cylindrical, with no distinct trace of tapering at either ex- 

 tremity, the anus blunt; lateral ridge well marked on thoracic, 



