INSECTS, DISEASES, AND INJURIES 



135 



turn brown early in the season and after repeated attacks 

 may die, European larch and tamarack, or American larch, 

 are subject to attack by this insect both in woodlands and in 

 ornamental plantings. 



The larva of the larch case-bearer crawls into a leaf which 

 has been burrowed out and carries this case as a protection for 

 its tender body. The insect passes the 

 winter in a partly grown condition within its 

 dark gray cylindrical case. At this time the 

 cases are about one-seventh inch in length 

 and are relatively slender. 



The hibernating cases may be observed 

 readily on infested twigs, lying flat on the 

 bark or projecting at various angles from 

 the twigs. In the spring the case-bearer 

 migrates with its case to the buds wnere it 

 burrows as far as possible into the leaf, but 

 retains a hold on the case. One larva will 

 attack and mine a large number of leaves 

 while it is completing its growth. 



When full-grown the larvae attach them- 

 selves and their cases to the bark at the base 

 of short side branches where they pupate, 

 emerge two to three weeks later and mate in a short time. 

 Early in June the females begin laying their brown ridged 

 eggs on the leaves of the larch. On hatching the larvae bore 

 directly through the eggshell into the leaf and burrow in the 

 tissues. Early in September the case-bearing habit is assumed, 

 using for a case either a portion of a leaf already mined or 

 perhaps a new leaf. In either event, the larva lines part of the 

 hollow leaf with silk, cuts off both ends, and migrates to new 

 leaves, carrying the case about in typical fashion. In the 



IG. The larch case- 

 bearer {Colcophora 

 laricella) . 



The tiny moths 



