XORTHUMnERLAXI) AND DURHAM. 219 



amiuation of all our British Polyommati, with their varieties, 

 and of the best figures of the European species, convinces me 

 that the only spots or ocelli that are never wanting are those 

 placed at the apex of the discoidal cell of each wing, and, con- 

 sequently, that either the absence or the presence of any one or 

 more of the others, and, a fortiori, their having jjupils or not, 

 affords no unvarying specific character. I might enlarge upon 

 this point, but refrain, and pi:oceed rather to apply the proposi- 

 tion to the insect before us. Mr. Gregson, of Liverpool, one of 

 our most observant Lepidopterists, is of opinion, founded on his 

 long and wide spread experience in collecting, that the full de- 

 velopment, and also the brightness of the ocelli in these insects, 

 depend much upon the W' armth of the season of their appearance 

 in the perfect state. x\ccording to this law, which certainly 

 obtains amongst insects generally, when undisturbed by local 

 causes, we might expect, and in fact find, that, in the southern 

 form of Agestis, the ocelli are the most brilliant, having the black 

 centres large and perfect. Still this is not always so, for not only 

 are some of those centres suppressed, but in many cases one or 

 more of the ocelli are entirely wanting. In our own locality, 

 where the connecting form Salmacis first appears in any numbers, 

 and where hundreds of specimens have passed through my 

 hands, the majority bear the impress of the southern type, 

 though few of them have the ocelli so brilliant as in specimens 

 from that 2:)art of England. These ocellated specimens are not 

 confined to such as have either the white or the black discoidal 

 spot on the upperside, but seem to occur indiscriminately. By 

 far the most interesting variety I have yet seen of this butter- 

 fly is one in my own cabinet, which I captured, in July, 

 1856, at Castle Eden, having the spot on the upper wing white, 

 with a black centre. Underneath, the only spots within the 

 orange band on its upper wings, are the discoidal — white, with a 

 small black centre, — all the others being entirely obliterated on 

 one wing; whilst, on the other, there is the sole addition of a 

 most minute one between the third and fourth nervures. On 

 both underw^ings, with the exception of the discoidal spot, and 

 the usual triangular blotch, every trace of ocelli within the same 



