II. A EUROPEAN ALDER SAWFLY LEAF-MINER 

 Kaliosysphinga dohrnii Tischbein 



The European alder {Alinis glntinosa) and its cut-leaved varieties 

 are often planted as ornamental trees in America where they have become 

 naturalized in some localities. In Europe the leaves of this alder are 

 preyed upon by several insects, and at least one of these enemies has been 

 injuring these trees in America for several years. 



In June, 1891, a nurseryman at Newark, N. J., sent me several leaves 

 of European alder with large brown patches or " blisters " on the upper 

 side, as shown in Fig. 29 



I soon found that a large tree on the Cornell 



.;<".>-. 



Fig. 29. — Work of the European alder sawfly leaf-miner. Several larvce 

 lived in the brown blisters or mines. Nearly natural size. 



University Campus, and one tree of the cut-leaved variety near the 



Campus also bore many of these " blistered " leaves. There were several 



small larv?e living in each large " blister " which they had caused by 



mining in the leaf just under the upper epidermis. The half dozen 



European alders planted on the Campus in later years were soon infested 



by the insects, and dviring the past season many of the leaves on these 



trees were so badly " blistered " that the ground beneath was strewn 



with the brown, dead leaves, and the trees presented a very ragged 



appearance from July till autumn. Thus the insect is capable of seriously 



injuring these desirable ornamental trees. A study of the life and habits 



of this alder pest was begun in 1891, but was interrupted for several 



years, and finally completed during the past year. 



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