ORDER HYMENOPTERA 221 



following winter in these cocoons as untransformed larvae 

 and the following spring in late April or early May trans- 

 form through tender whitish pupae into adults. 



This serious menace of these particular shade tree pests is 

 not easily controlled by spraying as the larvae being within 

 the leaf escape from much contact with the materials 

 used. Nicotine sulphate has been used with some degree 

 of success. 



The alder sawfly (Fenusa dohrnii), is another imported 

 pest attacking the European alder. It is reported to have 

 been at Ithaca, New York as early as 1891 and was common 

 there for several years previous to 1905. They mine the 



Fig. 67. The cherry or hawthorn leaf -miner, Profenusa collaris. 1, 

 male; 2, female. (After Parrott and Fulton.) 



leaves of alders, especially the European ones, early in June. 

 The blisters are large and often the mines so merge as to 

 bring several larvae into a common mine. The example is 

 from a European account by a Swedish writer, Ivar Trae- 

 gardh. The life history is very similar to that of its near 

 relative the elm-leaf sawfly. 



The Cherry and Hawthorn Sawfly, Profenusa collaris, 

 is a new orchard pest in New York. It is not recorded as 

 injurious to fruit plantings until 1915. As a hawthorn pest 

 this species is definitely known to occur in New York and 

 Massachusetts and it is doubtless a native species. Almost 

 the only notice of this species in our literature is a careful 



