164 Forty-first Report on the State Museum. 



tlie wing to its apex; veins brown. Expanse, 0.47-0.65 in.; length, Q, 

 0.20-0.30 in. 



For a more detailed description, see American Entoinologist, vol. i, 

 1869, p. 104, from which the above is abridged. 



A Second Acorn-cup Gall Insect. 



Since the publication of the above, as the only American gall that 

 is known to grow out of the acorn, a second species has been 

 described by Professor Eiley, as Cynips gall, Quercus glandulus. It 

 differs from the above conspicnonsly, in that the new gall is more or 

 less completely imbedded in the cup. It is a pip-like body, aver- 

 aging, when well-developed, one-fifth of an inch long by about one- 

 half so broad; its sides are either parallel or slightly bulging, more 

 or less deeply corrugate, and of a whitish-green color. The larva 

 occupies a cell near the flattened or slightly concave nipple-tipped 

 crown. The insect has not been described. The gall occurred in 

 October, at Toughkenamon, Pa., on a shade-tree of Quercus bicolor in 

 a pasture. Two-thirds of the acorn cups were affected. {Transactions 

 St. Louis Academy of Science, vol. iii, 1887, p. 577-8.) 



This species appears to have been overlooked (or perhaps omitted 

 from want of knowledge of the insect) by Mr. Ashmead, in his paper 

 above cited, In the Cresson Synopsis, it stands as Cynips ? glandidosus 

 Riley. 



Aulacomerus lutescens n. sp. 



The Poplar Saw-fly. 

 (Ord. Hymenoptera: Fam. TENTHREcmiDiE.) 



Larval Habits. 

 A number of saw-fly larvte were discovered in the early part of 

 June on a small poplar, Populus monilifera, in my garden, feeding in 

 parallel rows side to side on two leaves, which had apparently been 

 eaten from the tips downward. On the foot-stalk of the leaves the 

 scars of the egg-deposit from which they had been hatched were seen, 

 to the number of thirty in one and twenty-eight in the other. They 

 were probably the oviposition of one female. They fed heartily and 

 rapidly, abandoning one leaf when all but so much of the basal parts 

 as would afford them a convenient footing had been consumed, and 

 then passing to another. Some of the stronger veins were left uneaten. 

 Their social habits continued to maturity, although as they 

 approached this period, they separated into smaller groups, and 

 would at once do so if disturbed by the act of removing some of them 

 from the leaf. , , 



