AND TIIFJR TRANSFORMATIONS. jj- 



The caterpillar is groen, with a pale, aiigulatcd row of dorsal spots, and a central brownish line. It feeds, 

 according to Haworth, on grasses, but Esper figures it upon the wild .strawberry. It appears in this state in the 

 months of April and June. 



In the Entomological Magazine (vol. ii. p. 515) Mr. Newman endeavoured to prove that this species and 

 the two following "arc but one species." Specimens taken at Ramsgaie, Dover, Ilythe, Hastings, Rye, 

 Brigliton, Worthing, Little Hampton, Chichester, Portsmouth, Isle of Wight, Dorsetshire and Somersetshire, 

 exhibit the " typical form " of tlie species (as described above) ; at Birmingham, Worcester, and Shrewsbury, 

 "an evident change has taken place, the band of rust-coloured spots has become less bright; at Manchester 

 these spots have left the upper wing almost entirely ; at Castle Eden Dean they are scarcely to be traced, and a 

 black spot in the centre of the upper wing becomes fringed with white ; in some specimens it is quite white ; 

 the butterfly then changes its name to Salmacis. We proceed further northward, and the black pupil leaves the 

 eyes on the under side, until at Edinburgh they are quite gone ; then it is called Artaxer.xes." Mr. Stci)hens does 

 not, however, agree with Mr. Newni.an in this respect, stating that " his definitions do not accord with my series 

 of specimens of the three insects obtained from nearly every one of the locahties enumerated by him." (lUustr. 

 Ilaust. 4, p. 3!!2.) Boisduval also gives the Artaxerxes as distinct, stating that its fore wings are proportionably 

 longer than those of Agestis ; to which I may add that the relative position of the spots (which seems to me in this 

 genus to afford a good specific character) is different in the two species, especially on the under side of the upper 



DESCRIPTION OF PLATE XXXVII. 



Insects. — Fig. 1. Polyommatus Salmacis (the Durham Argus B. ). 2. Tlie female. 3. Showing titc unJcr side. 

 " Fig. 4. Polyommatus Artaxerxes (the Artaxerxes B.). 5. The female. 6. Slmwiug tlic under side. 



Plants. — Figs. 7 and 8. Ononis procurrens (trailing Rest-harrow). 



The insects on this plate arc all figured from the cabinet of Mr. Stepliens. I have placed tliese two species together to enable the collector 

 to compare tliem, as they have been supposed by some to be merely variations of one species. In Sal.amacis it will be seen the female is 

 sometimes without the white mark, wliich is more constant in Artaxerxes, and Salmacis has more frequenlly a slight indication of au orange 

 border on the foic wings. On the under side Artaxerxes is without tlie black p-,ipil in the pale spots, which is pretty constant in Salmacis. ll.N.H. 



SPECIES 14.— POLYOMMATUS SALMACIS. THE DURHAM ARGUS RUTTERFLY. 



Plate xxxvii. fig. 1 — 3. 



SvNONYMEs. — Polyommatus Salmacis, Stephens, Illust. Ilaust. vol. iii. p. 235. 

 Wood, Index Erit. t. 3, p. 73, <J $, .and fig. 12. Duncan, lirit. Hutt. pi. 31, fig. 2 and 3. 



This species is intermediate between Agestis and Artaxerxes, and varies in the expanse of its wings from 1 f'., 

 to li inches. The upper side of the wings is of a silky blackish brown colour, with a black spot at the extremity 

 of the discoidal cell in the males, and a white one in the females, wiiich is, however, sometimes obsolete, 

 especially in the latter sex. There is also a row of snbmarginal fulvous spots in the hind wings, which sometimes 

 also extends along the margin of the fore wings, but it is occasionally almost obsolete in the male. The fringe is 

 white, with slight brown marks at the base. Tlic under side of the wings is of a brownish grey, the anterior 

 wings having a white spot at the extremity of the discoidal cell, succeeded by a curved row of similar spots, caci, 

 marked in the centre with a dusky point ; there is also a submarginal row of orange spots bounded above with a 

 dusky crescent, and marked beyond with a dusky spot surrounded with white, the extreme margin being marked 



