1086 WaLteR H. WELLHOUSE 
All of the flies reared on hawthorns are equal in size to those reared on 
apple, not small like those. reared on the blueberry. Counts were made 
of the infested and the 
uninfested fruits from 
a square yard beneath 
each of ten trees of the 
three species first men- 
tioned in the preced- 
ing paragraph. The 
counts showed that 
from 20 to 25 per cent 
of the samples taken 
were infested by the 
Fre. 124. cross SECTION THROUGH A PINEAPPLE GALL maggots. 
HYMENOPTERA 
Tenthredinidae 
cerast Linn., Caliroa (Pear and cherry slug) 
The sluglike larvae of Calzroa cerasz were in a few localities so abundant 
that they defoliated a few native hawthorns and injured a number of 
others. In August, 1918, several trees on the Cornell University campus 
were completely defoliated, while neighboring trees were untouched by 
the larvae. 
Sawfly No. 1 ; 
On June 23, 1918, a.leaf of Crataegus pruinosa was found with a row of 
fourteen eggs inserted in the margin. The eggs hatched on June 28, 
and a row of little green larvae, with large, black heads and many black 
dots scattered over the body, began to feed gregariously on the edge of 
the leaf. All of them died within a few days. 
Sawfly No 2 
On May 24, 1918, several medium-sized sawfly larvae, bright green all 
over, were seen eating separately on the edges of Crataegus punctata 
leaves. 
Sawfly No. 3 
Sawfly larvae, with red heads and yellow bodies marked with black 
lines and dots, were found feeding on the leaves of Crataegus punctata 
in late August, 1918. They were feeding two or three together on a leaf, 
and fifteen larvae were taken from one tree. When they became about 
2 centimeters long, on September 1 and 2, they spun brown cocoons on 
the ground among débris. A tree with ten larvae of the same species 
