82 



THE YOUNG NATUEALIST. 



from Agestis is now well known ; the discoidal spot is white instead of black, 

 the marginal lunules are wanting or nearly so, and the white spots of the 

 underside have no black centres. So rare was this butterfly when first dis- 

 covered — it does not occur on the Continent — that Fabricius described it 

 without seeing a specimen, and we are told the custom obtained of pinning 

 a coloured drawing of it into the drawer, as an actual specimen was unobtain- 

 able. At this time, so far as I know, the larva was not known either here 

 or en the Continent. 



Salmacis was described (from specimens taken at Castle Eden Dene, 

 Durham), by the late C. J. Stephens, in the third volume of his "Illustra- 

 tions." In appearance it is intermediate between the two others, and 

 the place of capture being also intermediate between the Scotch and 

 English localities, the idea very naturally arose that they might all be forms 

 of one species, and the discovery of the larva now became of great importance. 



I do not know by whom the larva was first described. Zeller in the year 

 1840, recorded that " the eggs are laid on the underside of the leaves of 

 Erodium cicutarium, often several together but scattered." He described 

 the larva as "pubescent and greenish with darker dorsal line and rosy lateral 

 margins." At this time he did not succeed in rearing the imago. In West- 

 wood and Humphreys "British Butterflies," issued in 1840-41, the larva 

 was described as being "green, with a pale augulated row of dorsal spots 

 and a central brownish line." The food was again given as Heron's Bill, 

 Erodium cicutarium. This description of the larva, it will be observed, does 

 not agree with that by Professor Zeller, and in fact is not correct ; when 

 controversy arose on the subject, Professor Westwood admitted that he had 

 copied it, but had forgotten his authority. It was almost certainly from a 

 Continental source. By this time Artaxerxes had been found in many 

 localities in Scotland, and rather freely at Arthur's Seat near Edinburgh, where 

 Mr. Logan subsequently found the larva feeding on the common Sun Cistus 

 {Helianthemum vulgar e.) This discovery considerably affected the growing 

 opinion that Agestis and Artaxerxes were but one species, but no further pro- 

 gress was made then towards the elucidation of the matter. In Staintou's 

 "Manual" (Vol. 1. 1857), the two were given as good species, Westwood's 

 erronous description of the larva of Agestis being quoted, and the food given 

 as Erodium cicutarium, and Logan's manuscript description of the larva of 

 Artaxerxes with the food Helianthemum vulgare. 



In 1858, Mr. H. J. Harding, in the "Zoologist" claimed to have dis- 

 covered the larva of Agestis on Heron's Bill about eight years before, and in 

 the " Entomologists Weekly Intelligencer " for the same year, he offered to 

 supply any applicant who would send box and return postage, with larvse. 



