346 PROTECTION AGAINST INSECTS. 



3. Coleophora laricella, Hbn. (Larch-miner Moth). 



a. Description. 



Moth with wing-expansion of 9 to 11 mm. ; wings very 

 narrow, shining ashy-grey, with very long fringes, especially 

 to the hind -wings. 



Caterpillar 4 to 5 mm. long, with 10 prolegs, dark reddish- 

 brown. Pupa 4 to 5 mm. long, narrow, dark brown, with fine 

 bristles. 



b. Life-history. 



The moth flies in the daytime in May and June. 



The ? lays its little roundish yellow eggs on healthy larch 



Fig. 178. Coleophora laricella, Hbn. 

 a Moth, b Caterpillar, c Larval case, d Pupa. 



needles, usually only one egg on a needle. After 6 to 8 days 

 the eggs become grey. 



The caterpillars hatch in June, and continue to grow till 

 September. They hibernate on the needles in a case. The 

 pupal stage is passed from the middle of April till May in a 

 case on the needles. The moth emerges in the latter half 

 of May. 



Generation annual. Very common. The caterpillar is very 

 susceptible to late frosts, wet and cold rainy weather and hail. 



c. Relations to the Forest. 



This insect is a most dangerous enemy of the larch, and 

 prefers 10- to 40-year-old trees, but may also attack woods 

 which are older or younger than these. When other nutriment 

 fails, the insect attacks young spruce or pines that are either 

 under or among the larches. 



