182 PROTECTION OF WOODLANDS. 



85. The Pine Redn-gall Tortrix, Tortrix (Retinia) resinella. 



The wings of this moth have a span of only about 0*64 inches. 

 Head, body, and front wings are brownish-black or slate-coloured 

 with a copperish sheen. The upper wings have silvery-grey 

 transverse stripes, with a blackish feathery fringe, and the lower 

 wings are of a dark brownish-grey with soft light-grey edging, 

 whilst in both the under side is of a dark brownish-grey colour. 



The caterpillar is about 0'4 inches long, and of a yellowish- 

 brown colour. The chrysalis is 0*32 inches long, and dark in 

 colour, almost black. 



The life-history of this insect is remarkable, being distinguished on 

 account of its biennial generation, which is seldom among Lepidoptera. 



The moths swarm in May, the female depositing her ova singly 

 beneath the whorl-buds of young Pines, principally on the side 

 branches. When the young caterpillar comes out of the egg a 

 few weeks afterwards, it bores its way through the rind into the 

 soft shoot, and the resin which exudes from the wound thus made 

 forms a small soft gall about the size of a pea during the first 

 year; this serves the tiny, worm-like caterpillar as a place of 

 residence when hibernating during the following winter. In the 

 second year, on account of the continuation of the feeding of the 

 caterpillar, this gall increases to about the size of a cherry, and is 

 formed of thick walls of resin, but exhibits internally a distinct 

 partition formed by the gall of the former year. The shoot its 

 is hollowed out to the very pith, and is enclosed within the resii 

 gall. In April of the second year the caterpillar enters into tl 

 pupal state within the gall, and in the following month the mol 

 emerges from the chrysalis, coming head first out of the gall wh< 

 ready for swarming. 



The damage done by this insect is on the whole not vei 

 considerable, for, as above remarked, the side-shoots are principal] 

 attacked, and the leading-shoots only exceptionally, whilst th< 

 do not always perish in consequence. But when the insects 

 allowed to increase to any great extent, or when the young we 

 are growing on soils of only inferior quality, the damage done 

 the crops may frequently be quite considerable enough to mal 

 remedial measures advisable, and these can best take place 

 breaking off or crushing the galls of resin during the wint( 

 whilst the caterpillar is reposing within them. 



