NOTES, CAPTURES, ETC. 315 



suming them. The species of birds that congregate in these 

 districts in certain seasons are generally met with singly, or in 

 pairs ; and we have here analogous cases of birds and insects 

 illustrating the law of interdependance of plants and insects, and 

 of birds and insects, together with an elucidation of the causes of the 

 partial or perfect migration of certain species of both fornis. In 

 the case of the several s]3ecies named by Mr. Adkin, with wing- 

 less females and their swarms occurring at intervals of several 

 years, it is probable that such are regulated by the same cause : 

 but of British Lepidoptera I do not profess to know anything ; 

 there are probably other causes regulating the migratory instinct 

 of which we know little or nothing ; yet, this line of research, when 

 carefully pursued, affords a method of working out the causes 

 which regulate the numbers and distribution of certain species. 

 If we consider the great distance between Australia and New 

 Zealand (given in the ' Challenger' expedition at 1200 miles), I 

 doubt if any species occurring in New Zealand could sustain such 

 a flight across the intervening ocean. If Anosia plexippus is not 

 an old indigenous inhabitant of New Zealand, it could only have 

 reached the Islands from the east, and in such case the difficulties 

 would be much greater, and certainly I know of no artificial 

 means favouring its dispersion before the year 1840, as very few 

 European settlers had settled in the Islands before that date. 

 If migration from Australia could have any bearing on the 

 occasional abundance of Lepidoptera in New Zealand, we would 

 naturally expect the occurrence also of other strictly Australian 

 species, many of which are powerful fliers, but such has never 

 been observed here ; and although I do not fully agree with Mr. 

 Adkin's concluding remarks, I believe I have made it clear that 

 the general abundance of Lepidoptera and other Orders of insects 

 observed last season in New Zealand was not in any way affected 

 by migration, but the effect only of strictly local causes operating 

 under very favourable conditions. 



Ashburton, New Zealand, June 20, 1891. 



ENTOMOLOGICAL NOTES, CAPTUKES, &c. 



Entomological Pins. — The black-enamelled pin introduced a few 

 years ago, and now so generally adopted, is undoubtedly an advance on the 

 silvered pin previously in use, but our entomological pins are still open to 

 considerable improvement ; they should be firmer, and furnished with sharper 

 points. We do not now find so much verdigris in collections of Lepidoptera 

 where black pins are wholly used, and in the few cases where verdigris exhibits 

 itself, the cause is probably due to the fact that the pins with which the 

 affected insects are impaled had a portion of the enamel abraded when they 

 were inserted in the specimens. Users of black pins, the smaller sizes 

 especially, often find that two, or sometimes more, are stuck together. 



