66 Wisconsin Academy of Sciences , Arts and Letters. 
receptacle is often found between tbe intervening side ribs 
(Figs. 1 and 2). 
Extending transversely across the basal region of the recep¬ 
tacle is a single elongated, oval egg, with a distinction between 
dorsal and ventral surfaces indicated by a difference in cur¬ 
vature. The ventral, or convex side of the egg is always near¬ 
est the mid-rib, while the dorsal or concave side lies nearest 
the margin of the leaf (Fig. 1, e). The egg, soon after being 
deposited by the female, measures two and one-half millimeters 
in length. 
The following table shows the number of eggs deposited on 
the left and right sides of the mid-rib, the total number of eggs 
deposited, the number of eggs parasitized, the number of eggs 
hatched, the number of incisions, and lastly the number of 
partially completed receptacles, of one hundred leaves from a 
single peach-leaved willow and another hundred from a few 
long-leaved willows. 
Table I. 
Peach-leaved 
willow. 
Long-leaved 
willow. 
Eggs deposited on right side of mid-rib. 
207 
142 
Eggs deposited on left side of mid rib. 
Total number of eggs on one hundred leaves 
188 
138 
395 
280 
Total number of eggs hatched. 
Eggs parasitized by Trichogramma 
353 
251 
pretiosa . 
Eggs which failed to hatch from other 
5 
6 
causes. 
37 
23 
Incisions. 
109 
179 
Partially completed receptacles. 
74 
53 
On many leaves w r e observed only one egg deposited, but on 
others as many as six, eight, or even fourteen were found on one 
or both sides of the mid-rib. An examination of the one 
hundred leaves of the peach-leaved willow showed that nine¬ 
teen more eggs were deposited on the right side of the mid-rib 
than on the left side; whereas,, upon the one hundred leaves 
of the long-leaved willow there were one hundred and 
forty-two eggs on the right side of the mid-rib and one bun- 
