340 PROTECTION AGAINST INSECTS. 



April or May of the third year) ; the smaller one contains its 

 excrement. 



The moth flies about May ; the generation extending over 

 two years. As a rule the pine recovers its injuries ; but in an 

 unfavourable situation or after bad weather the attacked shoots 

 perish. The species is tolerably common in a few localities 

 in Scotland and in Windsor Forest. 



The treatment consists in the destruction of the galls during 

 the second winter, and in cutting off affected shoots. 



6. Tortrix rufimitrana, H.-Sch. 



a. Description. 



Moth with wing-expansion of 12-16 mm. ; fore- wings dark 

 greyish-brown, with lead-coloured wavy lines at their base, a 

 rusty yellow median band with a lead-coloured border, and a 

 round dark spot on a rusty yellow patch near the corner of the 

 wings ; hind-wings brownish grey, with grey fringes ; thorax 

 rusty yellow near the head, abdomen brownish-grey. 



Caterpillar 10 mm. long, with 10 prolegs, of a dull yellowish- 

 green above and yellow below, with reddish-brown head. 

 Pupa 6 mm. long, bright brown. 



b. Life-hislory. 



The moth flies from June till the end of July, sometimes 

 also in May. The eggs are laid on silver-fir needles, where 

 they remain during the winter. 



The caterpillars hatch in the succeeding spring, and when 

 fully grown at the end of June, let themselves down by threads, 

 and pupate in the soil-covering in a cocoon made of silk and 

 bits of earth. The moth appears 2 to 3 weeks later. Genera- 

 tion annual. 



c. Relations to the Forest. 



The caterpillar, commencing operations as the young shoots 

 appear in May or the beginning of June, eats the needles and 

 youngest shoots of the silver-fir. It devours the young 

 needles, bites off the older ones at their base and gnaws the 

 epidermis of the young shoots, spinning a thin web over the 



