ON THE HABITS OF EUURA. 39 



imperfectly kno^vn, so far as their life-history is 

 concerned. Both of them have been reared from 

 Tvillow twigs in ^vhich the larvse had passed the 

 pupal state, the twigs being hollowed out for about 

 one inch, and their vitality, to a certain extent, 

 destroyed. That they do not feed on the pith is, 1 

 think, certain ; and Mr. Edward Saunders has bred 

 E. saliceti from a bramble stem, the cocoon having 

 been spun about one inch from the end of the 

 broken branch. As with this bramble stem, it is 

 generally only in those willow twigs Avhich have 

 their points broken off that we find the Euura 

 larvse. 



I have been able this season to work out the life- 

 history of what is apparently an undescribed 

 species.* In May or June this species lays its eggs 

 in the leaf-buds of Salir caprea, in those buds, 

 namely, which are to give origin to the leaves of 

 the following year. Inside of these the larvse live 

 solitarily ; the buds become enlarged, somewhat 

 longer than they are when about to burst in spring, 

 and more than double the size of the natural buds 

 found on the tree at the same time. There is no 

 apparent change in the form of the bud, nor in the 

 outer skin. Next to this, however, is a firm layer 

 of a green substance, and the rest of the gall is 

 taken up with a bright green granular matter on 

 which the larvso feed. Towards the end of Septem- 

 ber or in October the larva leaves the gall-buds, 

 making, as it does so, an irregular, comparatively 

 large hole in one side and close to the top ; 

 creeps on to the twigs, and, if it finds one with the 

 end broken off, bores into it for an inch or so, 

 remaining there, in its cocoon, till the next summer. 

 If no suitable twigs are available it drops to the 

 ground. 



It is worthy of note that in the United States of 

 America there is a species of precisely similar 



*In my Moiiogr. Brit, Phyto. Hym. ii., I have described it as 

 E. nigritarsis. 



