74 " (.September, 



I collected a pint or two of galls ; were ash trees as accessible as 

 blackberries, J know trees that would have afforded bushels, and in 

 1887 I was unable to find any gall that was free from larvae ; the 

 number of larvae in an infested tree must, therefore, have been very 

 great, since I bred, chiefly during August, some 200 moths, every one 

 of which was of the black form {rustica), only four or five presenting 

 a slight shading that possibly represented the dark costal triangle of 

 Curtisellus. 



This seemed very strongly to suggest that rustica was a distinct 

 species, though it also appeared possible that rustica was the summer 

 brood of Curtisellus. I therefore followed rustica on through the 

 autumn, winter and spring, and kept a look out for Curtisellus, which 

 I did not succeed in finding till the spring, though then I succeeded 

 in meeting with it freely, still in its winter quarters. For brevity I 

 call the gall-feeder rustica, the ordinary form Curtisellus ; also using 

 the names more correctly, rustica for the dark, Curtisellus for the 

 typical form. 



The summer rustica lays her eggs in the galls from which she 

 herself was bred ; the young larvae live therein as their parents did, 

 until the approach of winter and the failure of the sap in the dying 

 galls forces their retreat. At this time some are still very small, others 

 are not far from half-grown ; in each case they burrow into the bark 

 or into a bud, a very common spot is at the base of the stalk supporting 

 the gall. Here, either in a burrow in the bark or in a bud, they pass 

 the winter, really hibernating, that is, having taken up their winter 

 quarters they do no more feeding till spring. I was unable by forcing 

 to make any of these continue to grow or make any progress in the 

 autumn ; but they, nevertheless, do hibernate at various ages. 



In April many may still be found smaller than others at date of 

 going into winter quarters. In the spring they become active when 

 the flower-buds of the ash begin to swell, and feed up, some few in 

 the bark, but the majority make their way to a bud, the interior of 

 which they devour, making their slight and flimsy cocoon among the 

 debris. This spring the ash was nearly a month late, and the. moths 

 probably so also ; they were on the wing on June 11th. 



July 28th, 1888. — Mr. Wood informs me that Curtisellus and dark 

 vars. are abundant on palings at Stoke. At this date I find a full- 

 grown rustica larva. 



However, I bred Curtisellus this spring at practically the same 

 dates (beginning of June) as rustica, and in so abnormal a season as 



