The British Butterflies Described 



fore-wing being traversed by a white line ; the hind- 

 wing has a similar white line, which forms a W at the 

 basal angle ; under it is a broad orange scalloped band, 

 edged with black and white ; the extreme outer edge is 

 black, and this black edging scallops into the orange 

 band. Tail black. 



The caterpillar feeds on Elm ; is pale green, with 

 yellow bars and two rows of whitish humps along the 

 back. It may be got by beating the Elm in early 

 summer. The Butterfly appears in July, but is far from 

 common, York being about its northern limit. 



THE BLACK HAIRSTREAK (Theda pruni), Plate XII., 

 Fig. 5. About the same size as the last, but many 

 individuals are smaller. The ground colour is almost 

 black, but near the tail are two or three conspicuous 

 grange spots, which are not present in w-Album. The 

 orange band on the under side of the hind-wing is 

 much bolder and is edged with black spots on both 

 sides, the inner row of spots being partially ringed with 

 white ; the white hairstreaks are fainter and slightly 

 interrupted. This is the rarest of the group, and con- 

 fined to a few localities in the South and South-East. 



The caterpillar is green, with yellow spots and lines ; 

 it is found on Sloe and Oak The perfect insect is 

 out in July. 



THE PURPLE HAIRSTREAK (Theda quercus}> 

 Plate XII., Fig. 3. The commonest and most widely 

 distributed of the Hairstreaks extending well into Scot- 

 land where, however, it is not common. The upper 

 surface in the male is shot with purple, while the female 

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