NORTHUMBERLAND AND DURHAM. 221 



(Brighton), and in many of the localities where Agestis is taken, 

 but they occur only sparingly, and in one spot, where I take my 

 finest specimens, and where indeed I caught the curious variety 

 you allude to (mentioned above), I have reason to believe the 

 Geraniums do not grow at all." Further, I may add tliat Mr. 

 Gregson, who has taken it in North Lancashire, Cheshire, Derby- 

 shire, Yorkshire, Lincolnshire and Wales, says: " I have never 

 taken Agestis, except where the Ileliantliemum grows." I might 

 multiply these instances, but refrain. They are pretty strong 

 indications that the larva of the southern form finds equally 

 with the northern one a pabulum in this plant. 



Having gone so far into the history of this insect, it may not 

 be amiss to examine into the geographical distribution of the 

 two forms it assumes, and endeavour to reconcile some differ- 

 ences as to its times of appearance in the perfect state. As I have 

 intimated above, the white-spotted variety, Artaxerxes, seems en- 

 tirely confined to Britain, ranging from Richmond (54|° N.L.) 

 to Kincardineshire (57° N.L.); and in Scotland from sea to sea 

 — Dumfries and Ayrshire to St. Abb's Head and Stonehaven. 

 Throughout all this district, as with us, it appears only once in 

 the season, from the latter end of June to the latter end of July. 

 Mr. Logan has once met with it in August. The black-spotted 

 variety, Agestis, has a wide European range, from Gibraltar in 

 the south (36'' N.L.) to Upsala in the north (60° N.L.), and 

 from England on the west, to the Ural Mountains, the confines 

 of Asia, on the east. Li England as far north as London and 

 Bristol, it seems to be double-brooded. May and August; whilst 

 at Liverpool and so northwards, only single, making its appear- 

 ance simultaneously with the Artaxerxes form here, and in Scot- 

 land during June and July. On the Continent, with the ex- 

 ception of Italy, it is included in the lists of every country I have 

 access to, but unfortunately few of these w^orks state its times 

 of appearance with the minuteness one could wish, and to these 

 latter only need I refer. Godart in his great work, vol. 1, p. 213, 

 gives it two broods, in spring and in summer, and says it is very 

 common in France. Dr. Boisduval, our first autliority in the 

 Diurna, in his " Index Methodicus" (1829), says: " Europa, Maii, 



VOL. in. I'T. IV. 1 D 



