Severin and Severin—Habits of the Saw-fly. 65 
a white fluid from the collateral sac is poured over the egg 
into the receptacle. Usually the insect proceeds in the same 
manner to deposit a second, a third, or more eggs, always tak¬ 
ing care to place but one in each receptacle (Fig. 1, e). FTo 
difficulty is experienced in observing the operation, the female 
saw-flies not having the timidity of many other insects and 
not being easily disturbed while laying their eggs. 
The whole process of depositing an egg occupies about one 
minute. Oftentimes a specimen was observed that made an 
incision (Figs. 1 and 2, i) or almost completed a receptacle 
(Figs. 1 and 2, pr), when the saw's struck a side-rib and the 
sawing ceased. Sometimes there w r as no side-rib to obstruct 
the sawing, but for some unknown reason an active female 
would not complete the receptacle, or, if she did, would not de¬ 
posit an egg. Specimens which were near the end of their 
natural life frequently cut a large number of incisions or re¬ 
ceptacles without depositing an egg. One specimen, wdiich we 
observed, cut fourteen incisions in one leaf and thirty inci¬ 
sions in another leaf without either completing a receptacle or 
depositing an egg. These specimens, when they did finally 
complete a receptacle and deposit an egg, required more than 
one minute for the vdiole process. Table I show's the number 
of incisions and partially completed receptacles found on one 
hundred leaves from a. single peach-leaved wfillow and another 
hundred from a few long-leaved willows. 
The receptacle is a little longer than wide (Figs. 1 and 2, 
r). It measures a little less than five millimeters in length 
and four to four and one-half millimeters across its widest re¬ 
gion. Upon the long-leaved willow 7 the receptacle is often 
smaller and is situated either near or against the mid-rib. 
Rarely does the receptacle extend beyond the mid-rib, being 
more often flattened up against it. Upon the peach-leaved wil¬ 
low the mouth of the receptacle (Figs. 1 and 2, mr) is about 
three millimeters from the margin of the leaf, and its base is 
usually four to five millimeters from the mid-rib except to¬ 
wards the apical end of the leaf where the mouth of the recep¬ 
tacle is somewhat closer to the margin of the leaf and the base 
often rests against the mid-rib. In both kinds of leaves, the 
5—S. & A. 
