324 NEW YOKK STATE MTSEUM 



numerous wounds made in the leaves. The young slugs commence to gnaw 

 small holes as soon as they hatch, those on one leaf usually feeding in close 

 proximity to each other, though they are hardly gregarious. The entire 

 leaf is devoured and the plant soon denuded, leaving only the thicker 

 midribs untouched. No effort is made toward concealment and they can be 

 easily distinguished by their black color and filthy moist excrement. Their 

 peculiar curved position is very characteristic of the group, the posterior 

 segments usually being turned so that they extend forward and not infre- 

 quently under a portion of the leaf on which the slug rests. The larva is 

 full grown in from 10 days to three weeks, at which time it descends to the 

 ground and forms a shining dark l)r()\vn cocoon, apparently composed of a 

 gluelike material. It changes within this retreat to a yellow pupa, and in 

 the course of a week the winged sawfly appears. Eggs are deposited in 

 the District of Columbia from May till the middle of October. This 

 species has been recorded by Dr Packard, as feeding on wild cherry foliage. 



Natural enemies. The eggs, according to Dr Howard, are frequently 

 destroyed by a small calcid, Trichogramma, which becomes very numerous 

 when the second brood of females is ovipositing. An ichneumon fly, 

 Ichneumon s u b c y a n e u s Cress., has also been reared from this 

 species, and the wlieel bug. Prion idus cri status Linn., is a very 

 efficient enemy of this species in the Southern States. 



Remedial measures. This species should be easily controlled by the 

 application of an arsenical poison, preferably arsenate of lead, wherever it 

 is abundant enough to warrant the exjx'nse. 



Bibliography 



1895 Dyar, H. G. Am. Ent. Soc. Trans. 22:304 



1896 Marlatt, C. L. IJep't .\gric. Div. Ent. Tech. Ser. 3, p. 50-51 

 1904 Chittenden, F. H. U. S. Dep't Agric. Bur. For. Hul. 46, p. 70-72 



