43 



This species averges about an inch and a quarter in the expansion of its 

 wings. On the upper side it is a very dark brown, sometimes almost black, 

 and has near the hinder edge of the hind- wing a few orange spots. This last 

 character will at once distinguish it from the previous species, W-album. On 

 the underside it is an ashy grey, and has a broad band of orange, with a 

 row of black spots on its inner edge, and a silvery blue line. 



The caterpillar is green, with oblique yellow lines on the sides, and dark 

 marks down the back. It feeds on blackthorn in May. 



The chrysalis is brown, obese, with lighter markings, and darker tubercles. 



The butterfly emerges at the end of June or July, and frequents woods in 

 Central Europe, France, Italy, Scandinavia, Ualmatia, and the mountainous 

 districts of Western Siberia. In this country it is confined to very few 

 counties : Huntingdonshire, Northamptonshire, Buckinghamshire, Derby- 

 shire, and the extreme south of Yorkshire. 



It was not known to be a British species until September 1828, when a 

 member of the Entomological Club, purchased a number of specimens from a 

 Mr. Seaman, then a well-known dealer in objects of natural history, and resident 

 at Ipswich. The purchase was made under the impression that the butter- 

 flies were the Black Hair-streak (W-album), then a desirable insect to obtain. 

 Seaman, unconscious of the value of his capture, had given the real and 

 familiar locality of Monk's Wood, in Huntingdonshire, as the habitat, but as 

 soon as it was known that the butterflies were not the Black Hair-streak at 

 all, but a species new to Britain, he determined to move the mine of wealth 

 to Yorkshire ; and Mr. Curtis, who shortly afterwards published the butterfly 

 under its correct name, gave Yorkshire as the county where it had been 

 found. 



In an appendix to his "Illustrations of British Entomology/' 1834, Mr. 

 Stephens writes, " The insect occurs in profusion in Monk's Woods, Hunts., 

 towards the end of June, at which period it was taken by C. C. Babington, 

 Esq., and in the beginning of J uly 1 had the pleasure of capturing it there 

 myself." 



In 1832, several were taken by Mr. Henderson, in Melton Wood, near 

 Doncaster. 



In 1837, my father met with it as late as the 17th of July; and in 1842, 

 Mr. Doubleday as early as the 18th of June. 



In the Zoologist for 1852, the Rev. W. Bree writes, Thecla pruni is very 

 uncertain in its appearance. In 1837, it literally swarmed in Barnwell 

 and Ashton Wolds, Northamptonshire. I do not scruple to say that it would 

 have been possible to capture some hundreds of them, had one been so dis- 

 posed ; for the last few years it has appeared very sparingly indeed." 



