1 QQ [January, 



Now come the dark days. Part of June, 1877, was damp and ,' 

 broken ; not at all the bright warm skies L. Arion loves (1876 was very 

 hot for part of June). In dark cloudy w^eather they are always still, 

 and, I believe, they will only deposit their ova when the sun is warm 

 and bright. In 1878 the weather was worse, there being hardly a fine ; 

 day in the month. 1879 was yet worse than '78, and since then until 

 this season the same class of weather has been prevalent. ISfow, 

 during all these seasons I have gone or sent many times at the time 

 L. Arion should be out. In 1878, not over a dozen were seen, mostly 

 worn and weather-beaten, for there were hardly ever two consecutive 

 fine days. In 1879 they were yet scarcer, while in 1880, if my memory 

 serve me rightly, only two were obtained, and two or three more 

 seen. For the four years, 1881 — 84, not one has been seen in the 

 Gloucestershire district that I have been able to trace. 



I will now say a few words about the distribution of L. Arion. 

 Such years as it has been rare, it appeared to be entirely confined to 

 two or three spots of very limited area, whereas when commoner, and 

 especially in 1870, it cropped up here and there nearly all through 

 the country between the two chief "head quarters," which are nearly 

 three miles apart. It also occurs in two or three other localities, one 

 of them being over ten miles away, but everywhere it is limited to 

 small areas. 



One point of interest would appear to be this. My friend Mr. 

 Merrin used to take the species about a quarter or half a mile furthei 

 west than I have ever done, and at that time he knew of no othe] 

 locality. Since I have been acquainted with the species, not one haf 

 been taken in this old locality, although often visited at the righ 

 time. So local does it seem, too, that, although I have taken it freely 

 up to a certain point, I could never find a specimen beyond the sidei 

 of this one old quarry, in the direction of the old head quarters! 

 notwithstanding that the formation of the ground, herbage, &c. 

 appear identical with that where it was common. ^ 



Now, what is the probable cause of the diminution or extinctioij 

 of L. Arion ? To my mind the greatest, if not the sole, cause ha 

 been the continued prevalence of unfavourable w^eather, which aliki ^^ 

 caused an immense decrease in the blossoming of the wild thyme, an< 

 prevented free oviposition by the parent butterflies. It will be note< 

 that with continued and increasing fine weather, 1866 — 1870, thi ^ 

 species gradually increased also, until in 1870 it was common. Thai % 

 followed broken seasons, with irregular appearance of the butterfly 

 but still in sufficient number to take advantage of the fine June o 



