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parasitic and predaceous insects, as the snail-like appearance 
may, perhaps, cause some of their enemies to pass them by. 
A better protection, with which most false-caterpillars are pro- 
vided, is their power to secrete and eject an acid fluid from 
small pores in the skin. Whoever has passed through a wind- 
break of willows infested with the large, pale-green saw-flies 
of the American Cimbex, will have felt the rain of acid fluid 
produced by the worms overhead. Other saw-fly larvee are 
covered with a downy material that effectually hides and pro- 
tects them, while still others produce genuine galls like the 
willow-apple, or live inside of solid wood. While in this larval 
stage some of them do great damage by devouring the foliage 
of trees and various plants. Some gnaw holes through the 
leaf, others eat the entire leaf, while still others eat only the 
soft parts, leaving the skeleton of the leaf. Though a few 
species form galls and feed inside of these, they all spin, when 
ready to pupate, a papery cocoon, inside of which they change 
to pupeze. ‘These cocoons are hidden in various places, below 
the surface of the. ground, just above it, or inside of various 
other substances, while some are fastened to the food-plant 
itself. In this condition, most of them pass the winter, some 
of them remaining larve until spring-time when they change 
to pupze and soon after to adults. They are, most of them, 
small insects with transparent wings and broad squarish heads 
and robust bodies. Some, however, are very large, as for 
instance, the worst.enemy of our wind-breaks, the American 
Cimbex, which is an insect almost as large as a big hornet. 
When flying in large numbers over the tops of. willows, just 
before laying theireggs, it requires strong nerves to catch 
them with the fingers. Very few persons will dare to do so, 
yet the insects can not sting. They possess in place of this 
defensive, sometimes offensive, organ, a pair of saws by means 
of which they split leaves for the reception of their eggs. 
Even this organ is lacking in the males, and these insects 
can, consequently, only bite with their mandibles but can 
not seriously injure the fingers that hold them. The name 
saw-fly is, like many common names of insects, misleading, for 
they are not flies at all but wasps. The term saw refers to the 
small, double saw of horny material, which is fastened to the 
ventral side of the abdomen, and which is used to split leaves 
