465 
Wasps, Bees, and Ants 
leaving the skeleton of tough, fibrous veins; often only the upper surface 
of the leaf is fed on. Some of them cover the body with a white, waxy secre¬ 
tion, and some, when disturbed, emit a 
malodorous fluid from the mouth or from 
pores in the skin. When full-grown, they 
crawl down to the ground, burrow into it, and 
pupate within a little cell sometimes lined 
with a thin silken cocoon. Some of the larvae , 
.. . ,, . . , . . . Fig. 652.—Ihe currant-slug, larva 
live in gall which develop about them; one of the currant saw-fly, Nematus 
such species is common on willows. The ventricosus. (Two and one-half 
adults mostly have rather broad somewhat times natural size -) 
flattened bodies and head, are quietly colored, blackish, reddish, brownish, 
and usually quietly mannered, but fluttering about in the trees at egg-lay¬ 
ing time. 
It has been noted that numerous species of saw-flies can produce young 
Fig. 653.—The currant-stem girdler, Janus integer , a saw-fly at work girdling a stem 
after having deposited an egg in the stem half an inch lower down. (Photograph 
by Slingerland; natural size.) 
from unfertilized eggs (parthenogenetic reproduction), and in some species 
