NOTE ON THE EGG-LAYING HABITS OF EUCHLOE CARDAMINES. 209 



this respect than most butterflies, for on Friday, April 27th, when the sun 

 was shining, but the day too cold for Gonepteryx rhainni to be on the wing, I 

 had two pairings of £'.ca/Y/«»(i?<es in my butterfly-house, the insects having 

 emerged at this early time through the pupae having been kept indoors 

 through the winter. The ova, which I saw laid, were deposited singly 

 on the stalks of the flowerheads and unopened buds of Erysimum, the 

 butterfly pausing in her labours to feed, after laying a few eggs ; indeed, 

 I watched one on several occasions suck the honey from the very flower- 

 head beneath which it had laid the ovum. 



Although I succeeded in catching two female and six male specimens 

 of Gonepteryx rhamni before April 20th this year, I was unable to get 

 them to pair in my butterfly-house. The males, indeed, were assiduous 

 in their efforts to effect a pairing, but the females invariably refused 

 by cocking up their bodies, and must, I suppose, have already mated, 

 as they laid ova freely enough afterwards. Whereas, moreover, the 

 males of E. cardamines flew ofl' almost at once when the females showed 

 unwillingness, those of G. rhamni were most persistent, and the female 

 seemed to enjoy their attentions. The male would flutter beneath the 

 female, striking up against her with his antennae from time to time, while 

 both danced like gnats, but were otherwise almost stationary in the air. 

 Sometimes they used to fly upward, sometimes downward, till after a 

 few minutes the female appeared to tire of the game, and settled on a 

 leaf or twig, with her body still cocked up, and her wings, not merely 

 flat, but depressed, so as to eft'ectually prevent all approach by the male. 

 He, however, still tried to eflect copulation, and even crawled over 

 her outstretched wings as she rested. When finally she flew 

 off, she did so fluttering as before, and the male recommenced his 

 efforts, still dancing underneath her. At last, after about ten minutes 

 of unsuccessful courting, he flew away, only to begin the whole affair 

 over again when he met her some ten minutes later, having evidently 

 gained nothing from experience. 



It was not until the females had been in my butterfly-house for 

 more than a month that oviposition commenced, but perhaps the 

 prevalent cold weather had much to do with this. The ova were 

 deposited singly, but often two or more on the same leaf, generally on 

 the undersides, but sometimes also on the upper surface of the leaves 

 of Ehamnus frangnla. They, like those of E. cardamines, are of a 

 milky-white in colour when first laid, but darken afterwards. On 

 May 29th, I took one of the females, which I had observed to be ovi- 

 positing, out-of-doors to a small plantation of Ehainnns frangula and 

 R. cathartic ns, which I had made this winter. On my giving her her 

 liberty she at once commenced laying ova on the Rhamniis frangula, 

 but though she flew in and out of the shrubs of E. catharticus, which, were 

 interspersed with it, she never once laid an egg on them. I watched 

 her for about half-an-hour, during most of which time she was busy 

 egg-lajdng. After depositing about half-a-dozen eggs, she would rest 

 a few minutes on the ground or on a stone. Towards the end her 

 instinct appeared to fail her in a curious manner, as she actually laid 

 an egg or two on a box-border growing underneath the Ehamnus. But 

 I have frequently observed butterflies in my cage make similar mistakes, 

 and they appear to be guided only by the smell of the plants when 

 making their choice. Several times I have seen Papilio machaon lay 



