1 8 The Scottish Naturalist. 



about the time that the butterfly should have been common 

 there, did not observe a single specimen, greatly militates. 



Let us now see what can be said in support of the theory of 

 British origin. In the first place, we have the specimen seen in 

 Perthshire in the spring. Now entomologists are comparatively 

 few in numbers, and not many lepidopterologists go in pursuit 

 of butterflies early in spring. It follows therefore then, if one 

 was observed, there may have been others that did not come 

 under notice. By these eggs would be laid, and as 1872, 

 though a bad year in most places for perfect insects, yet ap- 

 pears to have been the reverse for larvae, the abundance of 

 specimens seen in autumn is accounted for. That is, if we 

 adopt Mr. Barrett's theory, that eggs are laid every year in this 

 country, but that the young larvae are usually killed off by the 

 dampness of the climate, the hot weather of the first three weeks 

 of last July saving them in this case from their usual fate. For 

 my own part, taking into consideration the great tendency to 

 irregular appearances in abundance shown by many of the 

 Vanessida, I think that the old idea of these insects remaining 

 in a dormant state in some period of their existence (possibly 

 that of the egg) has not been entirely explained away. 



Secondly, 1872, with its peculiar weather, has, strange to 

 say, been characterised by the appearance in various parts of 

 Scotland of insects rarely or never before seen in these parts- 

 Thus we have Vanessa polychloros in Aberdeenshire, Colias 

 Edusa at Perth (both species subject to irregularity in the 

 periods of their appearance in abundance), and Gonepteryx 

 rhamni in Fife. The two first can find their food- plants any- 

 where, but buckthorn, the food-plant of G. rhamni, is a rare 

 plant in Scotland, and I do not know what plant would do 

 for a substitute — sea-buckthorn, Hippophae rhamnoides, which is 

 naturalized on some parts of the Fifeshire coast, would scarcely, 

 I imagine, serve as such. Putting aside, therefore, Colias Edusa 

 and Gonepteryx rhamni as stragglers from elsewhere (which 

 rather tend to support the theory of immigration), we have 

 Vanessa polychloros, a species subject, like V.antiopa, to irregu- 

 larity, and like it a feeder on trees, occurring simultaneously 

 with Vanessa Antiopa in Aberdeenshire, and possibly also in 

 Perthshire. This fact may of course be adduced as an argu- 



