THE PEACH AND PLUM SLUG. 93 
observations seem to indicate that the females normally infest the 
lower branches first, gradually going higher and higher as the destruc- 
tion of the lower leaves progresses. 
On September 15 occurred a very hard shower, accompanied by 
a high wind, that destroyed a large percentage of the larve that were 
on the trees at the time. This constituted another setback from 
which the species had hardly recovered when cold weather set in. 
On October 5 practically all of the accessible foliage of the trees in 
the yard was examined and no stage of the sawfly found, except 8 
eggs. These were all located on one 
leaf and had apparently all been para- 
sitized. 
In the earlier attempts at life- 
history work great difficulty was ex- 
perienced on account of the delicacy 
of the young larve and the large 
death rate among them when trans- 
fer by hand from one leaf to another 
was attempted. In addition to this, 
it was found impossible to follow a 
given lot of larve through to maturity 
if left on the tree, because of their 
habit of moving over considerable 
areas and their consequent loss. The 
attempts to curb this tendency re- 
sulted only in the death of the larve. 
Also, the adults refused to oviposit 
under any form of restraint. For 
these reasons a special method of pro- bok Fr ae 
F Fic. 23.—Cage used in rearing the peach and 
cedure was adopted anda special — piumstug: a, Tumbler; b, sand for pupation 
rearing cage designed. Many unin- of the insects; c, tube, open at both ends, for 
5 moistening sand from bottom; d, vial of 
fested terminal clusters of leaves were — water for keeping food fresh; e, lantern 
marked with blank stringtags. These  chimmey; J, cheesecloth cover; g, rubber 
eC ar band. Reduced. (Original.) 
clusters were examined daily, and 
when eggs were found on any of the leaves the infested leaves were 
marked by clipping the tips and a lot number was placed on the tag, 
the number corresponding to a card on which notes were recorded. 
The leaf cluster was then allowed to remain on the tree until just 
before or just after the hatching of the eggs, when the whole cluster 
was cut off with a long stem and transferred to the rearing cage. 
This cage (fig. 23) consisted of a tumbler of sand, into the center 
of which was thrust a vial and at the side a tube open at both 
ends. The stem was placed in water in the vial and held upright by 
a perforated cork. The tube reached well toward the bottom of 
the tumbler, and was for the purpose of watering the sand without 
