CHERRY PESTS 
Detober. 
793 
8 
When present in large numbers, they 
soon cause the leaves to become brown 
and the trees to look as if they had been 
badly scorched by fire. The adult insect 
is a small shining black fly with four 
smoky transparent wings, the smoky ap- 
pearance being caused by a dusky band 
across the middle of the wings. 
count of the saw-like ovipositor with 
which the insect makes incisions into the 
leaves, this insect and a number of closely 
allied species are known as saw flies. 
Life History and Habits 
Searching out a suitable place, the adult 
fly pushes the ovipositor rather slowly 
into the under surface of the leaf and 
and Pear Slug. 
—After Ewing. 
Larva of Cherry 
Fig. 4. 
On ac- 
Diagram of Life Cycle. 
(Iowa Bulletin 130.) 
makes a small oval-shaped pocket into 
which the egg is placed by means of the 
ovipositor. When the pocket is being 
.made the tissues are so cut as to prevent 
their growing around the egg and de- 
stroying it or preventing the escape of 
the larva. 
The egg is almost colorless and is flat- 
tened on the lower side. As soon as the 
eges hatch the young larvae make their 
way to the upper surface of the leaf and 
begin feeding. At first they are yellowish 
white in color and without slime. In a 
very short time, however, as the slime 
spreads over the body, they change to a 
dirty green and have more the appear- 
ance of a. slug than of an insect. Imme- 
diately upon hatching they begin feeding 
on the upper tissue of the leaf, eating 
out numerous small patches, so that a 
number of slugs working on the same 
leaf will leave nothing but the dead 
brown skeleton of veins. 
After completing their moults the lar- 
vae do not feed any more, but crawl or 
drop to the ground, work their way into 
the soil from one to three inches and 
pupate. After moulting the last time, 
they do not again assume the slimy pro- 
tection, and instead of being green they 
are of a yellowish orange color with two 
minute black eyes. After the larvae 
crawl into the ground an oval cell about 
five-tenths inch long by three-sixteenths 
inch wide is made. 
