84 



THE YOUNG NATURALIST. 



it was nothing more than an opinion in 1867), that Artaxerxes and Agestis 

 were but forms of the same species. "It appears/' he says, "now to be 

 generally accepted that Lycana artaxerxes in only a variety of L. medon. 

 f J he former in the larva state feeds on Helianthemum vulgare. Although it 

 appears to ine extremely improbable that the larva of L> medon should habit- 

 uate itself to this food, and although I even doubt whether it could be fed 

 with species of Geranium, yet I will endeavour to make some experiments on 

 this head I do not recognize in my four English Salmacis any tran- 

 sition to my ten specimens of Artaxerxes, in all of which the black transverse 

 streak in the white discoidal spot of the anterior wings is entirely wanting." 



In 1868, the late William Buckler figured and described the larva of 

 Artaxerxes, from specimens found at Edinburgh. The descriptions of Agestis 

 given by Professor Zeller and that of Artaxerxes by Mr. Buckler might well 

 apply to the same larva. I find no further record on the subject till 1879, 

 when I made a systematic search at Black Hall Rocks near here, and found 

 five larvae feeding upon Helianthemum. These were forwarded at once to 

 Mr. Buckler, who in expressing his pleasure at their discovery, informed me 

 he could detect no difference between those 1 sent, and his figures of Artax- 

 erxes. The following month he successfully reared three butterflies, and 

 singular to say, these three, while most resembling Salmacis on the underside, 

 had on the upperside the characteristics of the three different forms, one being 

 Agestis, the second Salmacis, and the third Artaxerxes. This result made 

 Mr. Buckler more anxious still to obtain larvae from a Southern locality, and 

 in the September following, Mr. Jeffrey sent him eggs deposited by a typical 

 Agestis in Kent. These eggs were deposited on Helianthemum, on which the 

 larva fed. The butterflies were produced the following year, and thus was 

 Mr. Wailes' prophecy fulfilled twenty years after it was made, I have now 

 traced the butterfly from the earliest notice of it, down to the time when Mr. 

 Buckler bred every form of it from larvae, from the localities of their named 

 varieties, all the larva feeding on Helianthemum. 



But what about the Erodium? Professor Zeller had proved just as conclu- 

 sively that the species fed on this plant, as the British collectors had proved 

 that it fed on Helianthemum. The question now arises, will British larvae 

 eat Erodium, or will Continental larvae eat Helianthemum? Both these 

 points are yet unsettled, and I will briefly note what has been done or re- 

 corded on the subject. First there is Professor Westwood's statement that 

 the larvae fed on Erodium. This was published in 1840, the year in which 

 Professor Zeller first found them. It may be that Westwood's forgotten 

 authority for his statement was Zeller himself, though W estwood's description 

 of the larva is not correct. It may even be that the laiva of Hyper a fascicu- 



