NOTES ON THE LIFE-HISTORY OF THE LARCH CASE- 

 BEARER (COLEOPHORA LARICELLA.) 



Glenn W. Herrick. 



This is an European insect that is gradually becoming quite 

 widely distributed in the northeastern United States and 

 parts of Canada. It is also evidently causing considerable 

 injury to larch trees wherever it is present. 



It was first noted in this country by Dr. Hagen, who, in 

 1886, recorded it as seriously injuring the European larches on 

 an avenue in Northampton, Mass. In 1905, Dr. Fletcher 

 recorded its injuries to larches in Canada and in 1906 Miss 

 Patch says that the case-bearers have been present in certain 

 counties in Maine and "although minute they have been present 

 in such enormous numbers that larch trees have often been, 

 during the past three summers, eaten bare of green early in the 

 spring." The insect has been present on the larches in the 

 vicinity of Ithaca for several years, and undoubtedly does con- 

 siderable injury every season. The small green leaves are 

 devoured in early spring as fast as they push out, and on many 

 trees the green tissues are eaten out and the leaves left pale 

 and bleached in early spring. As soon as the buds begin to 

 break in the spring, the dark brown, cigar-like cases that have 

 been lying quietly attached to the branches all winter., become 

 suddenly animated and commence crawling to the tender green 

 leaves. In the spring of 1910 we found them active and feeding 

 by the 16th of April. Each larva selects a leaf and soon eats 

 a circular hole through the epidermis, thus gaining access to 

 the tender tissues within. Then holding its case at right 

 angles to the leaf and never releasing hold of its case it mines 

 to the right and left of the opening as far as it can reach. The 

 mined portion of the leaf assumes a bleached appearance and 

 the whole tree soon shows the effect of the injuries if the larvae 

 are abundant. Observations would seem to indicate that the 

 larvae molt just before leaving their winter quarters on the 

 branches. This point, however, must await another season 

 for definite determination. The cases of the larvae are enlarged 

 after they have been feeding a few days by slitting the old case 

 and inserting a piece of leaf in the slit and fastening it in with 



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