60 ±hi£. ENTokoLoGis*. 



And here I think we may conclude this very lengthy sub- 

 section, and for the present take leave of the two most interesting 

 and instructive colours that it has been my fate to meet with 

 during the course of this investigation,* 



(To be continued.) 



ON THE OCCASIONAL ABUNDANCE OF CEETAIN 

 SPECIES OF LEPIDOPTEEA. 



By Robert Adkin, F.E.S. 



A THEORY founded upon such careful observations as are 

 recorded by Mr. W. W. Smith, in his able article on the ' Abun- 

 dance of Lepidoptera in New Zealand' (Entom. xxiii. 305), is of 

 considerable value in elucidating this interesting problem, not 

 only in its bearing upon such phenomena in that district, but 

 equally so in other parts of the world. As this gentleman has 

 kindly referred to, and commented upon, a paper on a similar 

 subject for which I am responsible, an abstract of which 

 appeared in this journal (Entom. xxiii. 177), I propose to offer a 

 few further remarks on the matter. 



The drift of Mr. Smith's argument appears to be directed 

 towards showing that seasons productive of luxuriant vegetation 

 are favourable to the abundant development of Lepidoptera. 

 Thus he says, "Less snow fell in the higher Alps (New Zealand) 

 during the winters of 1888 and 1889 than for the previous 

 twelve years, while the meteorological records show a corres- 

 ponding mildness of temperature, and a considerable diminution 

 of north-west or snow-melting winds. The summers following, 

 each have been dry and hot, and naturally adapted to the life- 

 habits of Lepidoptera ; all sijecies I observed during the past 

 season, from the earliest spring-appearing species to those 

 which appeared in late autumn, emerged in great numbers, and 

 were all beautifully-developed insects." (The italics are mine.) I 

 may say at once that I fully agree with the foregoing ; it has 

 always been my opinion, and in this I believe I am by no means 

 singular, that certain meteorological conditions are favourable to 



represent the reaction is entirely hypothetical, and no more or less hypothetical in 

 the one case than in the other, it is entirely immaterial which explanation we adopt : 

 the broad result is the same in either case, and my readers are perfectly welcome to 

 follow their own inclinations as to whether they amuse themselves by adopting the 

 equations given in the text, or the alternative offered here. 



* It may be surmised that I have forgotten my promise to fight out to the bitter 

 end my amicable controversy with Mr. Cockerell as to the genetic relations of 

 white, yellow, and red. I may assure my readers, however, that I am — like Scott's 

 hero — hmid immemor. But the matter is deferred for the present, not merely 

 because this sub-section is already so immoderately long, but also because there are 

 involved in such a discussion various entomological arguments which can be more 

 fitly introduced in Section VI., on the biological aspect. 



