﻿Abundance of lepidoptera in new zealAnd. 805 



May, the imago emerging in June. . Mr. Hodgkinson has met 

 with the larvae of this Ephestia in a mill at Preston, where they 

 were feeding on oil-cake. 



(To be continued.) 



ABUNDANCE OF LEPIDOPTEEA IN NEW ZEALAND. 



By W. W. Smith. 



The study of Mr. Adkin's paper, "On the occasional 

 abundance of certain species of Lepidoptera in the British 

 Islands" (Entom. 177), has afforded me much pleasure, parti- 

 cularly as I have devoted much time for some years past to the 

 same subject in New Zealand. The main facts adduced by 

 Mr. Adkin to account for the occasional abundance of certain 

 species in the British Islands will not, as I will presently 

 explain, fully apply to the same phenomenon in New Zealand. 

 These are what that gentleman termed " The migration and the 

 local causes theories." The British Islands and New Zealand 

 are both insular areas ; but while the former is separated only by 

 a few miles from the European continent, the latter is situated at 

 least one thousand miles from the continent of Australia. Both 

 areas are subject to an occasional abundance of certain species of 

 Lepidoptera. On the causes of this phenomenon in New Zealand, 

 I propose to offer some explanatory observations ; whether the 

 hypothesis I now advance to account for the great abundance of 

 Lepidoptera during the past season will be accepted, I cannot 

 say ; it is one not at present clearly understood by naturalists ; I 

 allude to certain seasons of exceptionally luxuriant growth and 

 floriferous display of the indigenous flora; such seasons are 

 peculiarly favourable to the development and economy of many 

 species of Lepidoptera, and the two last seasons in New Zealand 

 have been of this description. Less snow fell in the higher Alps 

 during the winters of 1888 and 1889 than for the previous twelve 

 years, while the meteorological records show a corresponding 

 mildness of the temperature, and a considerable diminution of 

 north-west or snow-melting spring winds. The summers follow- 

 ing, each have been dry and hot, and naturally adapted to the 

 life-habits of Lepidoptera ; all species 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. This phenomenon was not 

 limited to Lepidoptera, as the numbers of many species repre- 

 senting other orders appeared on a corresponding scale. 



Mr. Adkin mentions the case of Vanessa cardui and Plusia 

 gamma as having occurred in great numbers in the British Islands, 

 in cold wet seasons, when other species were much less common. 



