Report of the State Entomologist. 



173 



When large areas of the larch are infested, as tamarack swamps, it 

 will be useless to attempt to compete with the enemy. Its destruction 

 through any applications that might be made would be altogether too 

 costly to warrant the outlay required. The best that could be done 

 in such cases would be to fell the trees as soon as it is noticed that 

 they are dead or doomed, and before decay has impaired their value, 

 and use them for some of the many purposes for which the timber is 

 available. 



Nematus salicis-pomum Walsh. 



The Willow-apple Gall Saw-fly. 

 (Ord. Hymenoptera : Fam. Tenthredinidje. ) 



Walsh: in Proc. Ent. Soc. Phil., vi, 1866, pp. 255-256 (description of gall, 



larva, imago, etc.). 

 Norton: in Trans. Amer. Ent. Soc, i, 1867, p. 216-218 (description of larva 



and imago). 



Walsh-Riley: in Amer. Entomol., ii, 1869, pp. 45-49, f. 30 (general 

 account). 



Cresson: Synop. Hymenop. Amer., 1887, p. 159 (cited). 



The galls of this tentbredinid were observed June twenty-seventh, 

 at West Albany, N. Y., on willow, Salix cordata. Several of them had 

 been eaten into, making an irregular funnel-like cavity.' One that 

 was opened for examination had the interior wholly consumed and con- 

 tained, instead of the Nematus larvae, four small white, legless grubs, 

 which were probably those of a " guest-beetle," named b}* Mr. Walsh, 

 from its appropriating the gall of another insect, Anthonomus 

 sycophanta ; another, which had been but partly eaten, contained one 

 of these larvae. The eaten galls were more rosy-cheeked than the 

 others. None of the larvae were carried to maturity, their failure to 

 mature being, doubtless, the result of the galls having been collected 

 so early. 



An extended account of this willow-apple gall (with illustration), 

 and of the three guest-insects that usurp its shelter and its food, is to 

 be found in the American Entomologist (loc. cit. sup.). In it, Mr. 

 Walsh states that the eggs of N. salicis-pomum are deposited in a slit 

 of the willow leaf toward the end of April. The larva attains 

 maturity during the last of July ; it pupates within the gall, where it, 

 hibernates, and the winged insect emerges in April — from the six- 

 teenth to the twenty-fifth, as in large numbers, reared. 



