232 FOREST ENTOMOLOGY. 



important factor in the life-history of the insect — viz., that the gall 

 takes two years to reach maturity. The generation is therefore a bien- 

 nial one. The eggs are laid in May, just under the whorl of buds, 

 which are bursting, or about to burst, into the growing shoots. The 

 caterpillar bores into the pith, and this being the most active period in 

 the life of the plant, causes the growth of a hollow gall resinous mass, 

 about the size of a pea, and in this abode the larva passes the winter. 

 In the following spring the larva 

 continues feeding, but meanwhile 

 the gall rapidly increases in size to 

 that of an average gooseberry. A 

 section of a gall shows that it is 

 divided into two chambers by a strong 

 ^te»^\«-<rt^38ft vertical partition : in one the larva 



^BKB^^^^-^ lives and pupates, and the other 



^B^W^S^ contains its excrement. The pupal 



' period is very short, and the moth 



„. „„„ „ ,. . . ,, flies about May — the generation thus 



Fig. 229.— Retinia re.siuella. _ •' » 



extending over two years. 



It generally attacks trees from six to ten years of age, but, as a 

 rule, the injury to tlie forest, or even to individual trees, is very 

 trifling. 



The moth (fig. 229) has a wing expanse of 16 to 18 mm. Head, 

 antennae, thorax, and abdomen dark brown-green, or lightish grey 

 dusty covering. Fore wings dark black-brown, with shining grey 

 transverse lines ; hind wings grey-brown ; fringes pale. 



The larva is about 11 mm. long, and of an orange-brown colour. 



Family TINE^. 

 Genu-'i Hyponomeuta. 



In many parts of the country, more especially in lanes, we 

 often find bushes defoliated and covered w4th a sort of net, in 

 tlie interior of which are a large number of small larvae of 

 the genus called Hyponomeuta. They are popularly known as 

 the small " ermine moths," but they are comparatively large for 

 " micros." 



