112 THE MOTHS OF THE BRITISH ISLES. 



The Pale Oak Eggar {Trkhmra cratcegi). 



In its typical form the male of this species (Plate 50, Figs. 

 I, 2) is ashy grey, with a darker central band on the fore 

 wings ; and the female is dusky greyish-brown, also with a 

 darker band. The colour of the male varies in shade from 

 almost whitish (var. pallida^ Tutt), to blackish grey ; in the 

 paler forms the central band of the fore wings is often of a 

 purplish tint, and in the darkest forms the band is almost 

 black. The female var. pallida^ is pale buff. 



The eggs, which are brownish, inclining to reddish on the 

 micropylar area, are covered with dark grey hairs from the body 

 of the female and laid side by side in a chain-like arrangement 

 on a twig of hawthorn or sloe (those figured on Plate 5 1 were 

 deposited in a box, and not securely attached). From eight to 

 twelve is said to be the usual number in a batch, and each 

 female will deposit an average of 160 eggs. 



The caterpillars do not hatch out all at the same time, but by 

 ones and twos, at intervals spreading over a period of two, or 

 perhaps three, weeks. Several forms of the caterpillar have been 

 described, but the ground colour is generally more or less black 

 above and greyish on the sides ; the ornamentation comprises 

 interrupted white or whitish stripes, streaked or clouded with 

 reddish, and reddish warts ; the hairs are reddish brown. The 

 example figured on Plate 51 was from eggs laid by a female 

 moth in Selkirk, South Scotland. From the age of three weeks 

 until it became full grown it was black marked with yellow on the 

 back and orange on the sides ; hairs pale greyish mixed with 

 black ones, especially on the back towards the black, glossy, and 

 somewhat hairy head. It hatched on April 26, was reared on 

 plum, pupated early in June, and the moth, a darkish grey 

 female, emerged on July 31. Another caterpillar that hatched 

 on May i, and two others from still later hatchings, were then 

 in chrysalis. 



The caterpillar maybe found from April to June on hawthorn 



