148 Tue Microscope. 
bule the eggs are arranged in a single row, and each egg is pro- 
longed into a stem twice its own length, the egg-cell proper al- 
ways being directed toward the oviduct,while each stem is curved 
around the body of the egg immediately in its rear. Figure 3 
RDA ~~ 
a ee D 
iS 
Le} 
ae 
represents this peculiar arrangement, with isolated eggs to show 
the stem and its distal enlargement. A fecetious friend suggests 
that the former resembles the arrangement of the monkeys’ tails 
when those animals form themselves into a living suspension 
bridge across a tropical stream. 
These pedunculated eggs and the irritating poison are the 
insects only contribution to the gall. With the serrated tip of 
the ovipositor she makes an incision in the bark somewhat after 
the manner of the saw-flies, deposits the eggs with their stems 
directed upwards, and troubles herself no more. The egg proper 
develops into the grub-cell, the stem into the hollow projecting 
spine, and the woody partition in some way insinuates itself be- 
tween the ovum and the peduncle. Asthe whole matures it be- 
comes surrounded by the hard capsule from which the fly must 
gnaw her freedom. The remains of the membranes are distin- 
guishable as a delicate, colorless, transparent lining within the 
spine. The length of the egg, including the stem, as it lies in 
the ovarian tubule, is #s inch; the length of the mature spines 
roughening the gall is about 7 . inch, an increase comparatively 
enormous. 
There are many interesting queries, unanswerable except 
by inference, in connection with the development, the food and 
oxygen supply of the larva, and the time at which the mature 
fly escapes. Out of the same gall, direct from the tree, I have 
removed larvae, pups, and flies in December and February, and 
in June I have taken the larvae, and observed a single Cynips 
escaping. When are the eggs deposited, when does the image 
appear? 
The grub in the lower cell of the capsule, which it snugly 
fills, is removed from the atmosphere by the egg membrane, the 
capsule walls and the thickness of the gall tissue. The sup- 
