THE CANADIAN SPORTSMAN AND NATURALIST. 



lias been almost equable, we may take it as a 

 pretty sure guarantee that when spring com- 

 mences and rouses the insect world, it will 

 receive no check and those pupce and larvce 

 whicl) have lain all winter inactive, will, on 

 awaking from their torpor, find vegetation 

 ready to receive them. But on the contrary, 

 an intermittent winter season ; a succession of* 

 frosts and thaws is fatal in a groat degree to 

 Lepidopterous larvae, and pupce; by alternate 

 freezing and thawing, a species of fermentation 

 is induced causing muscadine in the larvce and 

 rottenness in the pupce, while exposing them 

 at the same time to the attacks of mice, chip- 

 munks and other enemies. These causes 

 combined with their natural enemies such as 



ICHNEUMONID/TC, CHALCinLK and TACHINin.K 



attacking the larvce, must result in a corres- 

 ponding scarcity. 



3. Migrations of insects are as well known 

 and established facts in entomology as those 

 of birds in ornithology, but the reasons for 

 them are not so clear. In birds it is usually 

 for the purposes of breeding or the physical 

 necessity of a climate more congenial to their 

 habits, and the migration is total and not 

 partial, except in the case of stragglers who 

 from weakness or wounds, have been com- 

 pelled to remain behind. Except in the case 

 of the locust (Locusta migratoria) I do not 

 know of any species of European insect 

 periodically migntory. Vanessa (Pyrcemis) 

 cardui is probably the only Lepidopterous 

 insect that has been met with far out at sea, 

 and evidently with a settled purpose to reach 

 some given point; but partial migrations from 

 one part of the country to another are frequent 

 and usually occur at the height ot the season 

 when the last brood has left the chrysalis, or, 

 if the species is single brooded, almost as soon 

 as it emerges. When I was at Fray Bentos 

 del Uruguay, South America, in February, 

 1859, the branches of small trees for scores ol 

 yards were defoliated and the clustered larvce 

 of a species of Vanessa allied to V. urticce 

 were bearing them down with their weight. 

 They were as thick on the bare -stems as bees 

 in swarming time — in clusters ot two or three 

 feet in length — I believe that within the dist- 

 ance of a dozen yards, I could have collected 

 eight or ten bushels of larvce. But in tun or 

 three days, they had all left the trees, and in 

 about a fortnight afterwards the insects could 

 have been caught by thousands. They were 

 flying in hundreds, rising in the air and settl- 

 ing like flocks of pigeons, but in a week after- 



wards, fifty could not have been taken iii the 

 same locality, where before they appear* 

 abundant. Where had they gone '"'.' Migrated 

 evidently and dispersed themselves over the 



country. These Vanessa' were bred On the 



spot, but it is no uncommon thing n> meet 

 with small s warm 8 or knots of butt 

 evidently not feeding, but congregated for some 

 other purpose, invariably occupying an isolated 

 piece of bare earth or rock, and this usually 

 on a warm, cloudy day. 



W. H. Edwards, " Canadian Entomolog 

 vol. x, p. 140 says : — 



"I have sesn very few Papilionida of any Bpeci 

 season up to date, except ajax, which lias been abundant 

 as ever, but of turnus, usually exceedingly plenty in 

 spring, I have seen scarcely half a dozen examples N 

 troilus and few phSenor. So Colias phQodici and all 

 Pierids have been remarkable for t lnir absence; but 

 butterflies from hybernating larva, or hybernating ima- 

 ges, in contrast with those from hybernating chr\ - 



have been abundant — Meliteas, Argynids Yanessans and 

 Satyrids. (in 2nd June. 1^77, J rode for several miles 

 along a creek not far from where I live and PapilioS 

 swarmed. Passing a Hat rock by the sid ■ of the creek, 

 a space on it, which I computed as not less than four 

 feet square, was studded with Papilios as thick as tiny 

 could' stand ; when they rose it was like a cloud ; 

 nine-tenths of these were turnti.1. Allowing one 

 square inch to each butterfly, and this is ample, there 

 wen- upwards of 2 niio butterflies in that miss, and I 

 passed lesser groups with every mile as I rod 

 that the total absence of the species this year is 

 remarkable. It would seem possible that the extreme 

 mildness of last winter allowed of the existence or activ- 

 ity of enemies (insect probably) who sought out and des- 

 troyed the chrysalids, but why <i/or should have escaped 

 is beyond my conjecture " 



This assembling of butterflies in particular 



spots in large numbers, rising simultaneously 

 into the air when disturbed, and settling in 

 I lie same place, is the normal action of batter- 

 flies just on the eve of migration, and the total 

 absence of Pdpalh turnus the following year 

 is the natural result of such migrations, no 

 or<v having been deposited previous to depart- 

 ure, thus those parts ot' the country to which 

 these swarms had migrated would have a 

 corresponding increase in numbers. In the 

 summer ol" 1857, a great number ot the Purple 

 Emperor (Apatura iris) visited England. 

 They swarmed in the streets and suburban 

 gardens round London : they might be seen 

 drinking in the puddles in the streets, and 

 hovering over flowers in the gardens ; they 

 were evidently tired and starved, and so far 

 from a twelve toot pole with a net at the end 

 being required to dethrone his majesty from 

 his lordly oak. he could be knocked down 

 with a hat, and boys were vending them all 

 crushed and broken for what they would fetch. 



