THE WILLOW CIMBEX. 
585 
of the eggs could be found either on the dead part of the twig or in the living por- 
tion just beneath. The eggs are deposited between the epidermis and paranchyma 
of the leaf. When looking over the plants from above, the place of oviposition is 
hardly perceptible, appearing as a very slight blister-like swelling, accompanied on 
one side by a faint ferruginous Hue, but otherwise not differing in color from the rest 
of the leaf. On the under side, however, these blisters were very plainly visible, 
being much paler than the rest of the leaf, and having, in the more developed con- 
dition, a reddish tinge. These blisters closely resemble those of other saw-flies, 
Fig. 194.— Cimbex of the willow : a, leaf containing the eggs ; b, willow twig with incisions ; c, egg ; 
d, young larva; e, mature larva; /, cocoon; g, the same cut away to show the pupa, Ik; k, saw of the 
fly, i. After Riley. 
which insert their eggs in leaves and are usually nearly circular in outline (some- 
times nearly oval), and distinctly elevated above the general surface of the leaf, 
though otherwise quite flat. They are always on the face of the leaf, usually-nearer 
to the outer margin than to the midrib, never on or near the midrib and rarely 
extending across one of the side ribs. Their number varies from one to nine or more 
on a single leaf. Where there are several they are generally situated in a longitudi- 
nal row, the individual blisters being then always separated by the intervening side 
