216 WHITE LETTER HAIR STREAK. 



middle in the secondary pair, and forming two acute 

 angles posteriorly, in such a manner as to resemble 

 the letter W ; behind this there is an irregular band 

 of orange-red, widest towards the anal angle, and 

 bounded on the inner side by a black line, which is 

 sometimes edged internally with white ; the margin 

 itself, as well as the projecting tailed point, is black, 

 sometimes tipped with white. 



The caterpillar is green, with three spots of deep 

 ml on each of the posterior segments of the belly, 

 and a double series of small dots along the back. 

 When about to undergo its metamorphoses it be- 

 comes brown. According to some authors it feeds 

 on the elm, while others mention the black thorn as 

 its appropriate food. 



This insect, as already mentioned, has been de- 

 scribed by most British Entomologists as the P. 

 Pruni of Linnaeus, who does not appear to have been 

 acquainted with it. Of late years it has occurred 

 in great plenty in some districts, but in general it 

 may be accounted scarce, particularly in the northern 

 parts of the kingdom. " The boundless profusion," 

 says Mr Stephens, " with which the hedges, for 

 miles, in the vicinity of Ripley, were enlivened by 

 the myriads that hovered over every flower and 

 bramble blossom, last July (1828), exceeded any 

 thing of the kind I ever witnessed. Some notion 

 of their numbers may be formed, when I mention 

 that 1 captured, without moving from the spot, 

 nearly 200 specimens in less than half an hour, as 



