4 Farmers’ Bulletin 1252. 
measures may be applied successfully the following descriptions and 
illustrations point out the differences in the pests. 
There are three common or injurious species of rose sawflies in 
the United States. They are the bristly rose slug,’ a native species 
closely resembling a European species with which it has been long 
confused; the European rose slug,? a species present in both Europe 
and North America; and the coiled roseworm,’ a species chiefly re- 
markable for its habit of boring into the ends of pruned shoots to 
pass its resting stage, and named for the curled or coiled position it 
assumes when feeding upon the leaves. 
THE BRISTLY ROSE SLUG. 
The bristly rose slug is by far the most frequently encountered rose 
defoliator, and a rosebush is seldom seen which does not show some 
traces of its work. It occurs in the States east of the Mississippi 
River and north of a line drawn from St. Louis, Mo., to Richmond, 
Va. Often all but the newest leaves are covered with work of the 
various stages of this species, the bush presenting a much-abused and 
sickly appearance. 
The eggs are laid in slits cut in the midrib of the leaf from the 
upper side. These slits are about one-sixteenth of an inch long and 
usually appear as small yellowish spots against the green midrib. 
The yellow color is due to the presence of sawdust, or drying plant 
tissue, torn out by the saw. 
The larva, as its common name suggests, is sluglike, greenish white, 
and clothed with long, rather stout hairs. Upon hatching from the 
egg the young larva begins its attack upon the leaves, usually from 
the underside and, eating all but the thin upper skin of the leaflet, 
furnishes as evidence of its presence skeletonized spots readily recog- 
nized by their white translucency. As the slug increases in size, its 
work changes from skeletonizing to hole-eating and finally to eating 
the entire leaflet, without regard for any but the largest veins. When 
full grown, the larva constructs an irregularly shaped cocoon of vary- 
ing thickness from a brownish to whitish transparent membrane. 
During the spring and summer this cocoon is placed without regard 
to other than temporary shelter on leaves, at the angles of twigs, and 
in such places, but the overwintering insects choose a place that is 
rather more protected, as in the ground. 
1Cladius isomerus Norton; order Hymenoptera, suborder Chalastogastra, superfamily 
Tenthredinoidea, family Tenthredinidae, subfamily Cladiinae. 
2Caliroa aethiops Fab.; order Hymenoptera, suborder Chalastogastra, superfamily 
Tenthredinoidea, family Tenthredinidae, subfamily Messinae. 
SBmphytus cinctipes Norton; order Hymenoptera, suborder Chalastogastra, super- 
family Tenthredinoidea, family Tenthredinidae, subfamily Allantinae. 
