74 LEPIDOPTERA. 



of frequent and usual occurrence, such as, for example, Thais 

 Honoratii and Argynnis Valezina, whereas others are ex- 

 ceptional cases that may never happen, except in the single 

 individual ; this is a wide and important difference, and it 

 would be well to adopt such a fourth term, — the word " lusus" 

 for example, would convey its own meaning. Besides these, 

 there are the varieties of the spring and summer seasons, 

 which Dr. Staudinger indicates by Gen. I. and Gen. II. — 

 spring and summer. We are all so apt to forget the distinc- 

 tions between these forms of variation, that it seemed best 

 to take this opportunity of entering into them at some length 

 — even at the risk of appearing somewhat to forsake the im- 

 mediate subject of the paper; but let us now turn to the list 

 itself. Our author conveniently divides the county into 

 eight parts, according to the rivers which drain it; it will suit 

 us better to regard Perthshire as one, and to arrange its in- 

 sect productions into Alpine species, namely, those which in 

 the British isles are exclusively northern in their distribution, 

 and, secondly, subalpiue and lowland, those which may be 

 met with in any part of our island. 



To examine, firstly, the Alpine species of the list, amongst 

 the butterflies we have — 



Ccenonympha Typhon, var. Laidion. — The north Scottish 

 and the Irish examples of Typhon are of this variety, pro- 

 minently brought before the notice of British Entomologists 

 by its being treated as a distinct species in Mr. Kirby's ex- 

 cellent "Manual" under the name of Typhon^ and also by its 

 capture near Killarney by Mr. Birchall, and by his kind dis- 

 tribution of the insect: it has few ocelli, one in the upper 

 wing, three or four in the lower. The English and south 

 Scotch specimens are the var. Philoxeiius, better known as 

 Rothliehi; the typical Typhon does not occur in Britain; the 

 Lapland var. Isis, according to our author, occurs in Perth- 



