THE HUISACHE GIRDLER. 7 
ovipositor, one side at a time, and then she searches for another suit- 
able location. The eggs are ordinarily placed between the layers 
of bark, and it may here be stated that this species does not deposit 
particularly about buds or at the base of smaller branches, but may 
lay her eggs anywhere along the branch girdled. It also might be 
added that, unlike some, this species of Oncideres does not make 
transverse incisions in the bark, presumably to prevent the growth 
of the branch from crushing the egg. 
There is, in addition, a difference from Oncideres cingulata and 
0. texana in the way this species leaves the egg after deposition, in 
that only a very slight gluey excretion is made in sealing the 
opening to the egg cavity, and at times there is none at all. This 
waxy secretion is very conspicuous with the work of the two smaller 
species. 
The larva feeds along gradually, leaving in its burrow behind 
excrement and castings well packed, which may prevent attack of an 
enemy from the rear. It has been observed that when a branch not 
completely severed remained in the top of the tree the young larvae 
would often perish, presumably for lack of moisture. On the other 
hand, the writer has noticed branches that remained several feet above 
ground all season and which developed beetles during October. It 
thus appears that it will depend upon the amount of rainfall and cli- 
matic conditions generally as to whether the mortality of the larvae is 
high in the suspended branches — well up in the tops of the trees. If 
there should be a moderate rainfall during the winter and spring 
months, it is thought that the mortality in these suspended branches 
would be very low, but on the other hand if it should be dry, the mor- 
tality would be high. While the larva will stand a very dry atmosphere 
for several months, its growth will not be as rapid as where there is 
sufficient moisture to permit constant feeding. Larvae that have been 
checked in growth from lack of moisture develop very rapidly when 
placed in more humid surroundings and appear to obtain their growth 
just as soon as when left under normal conditions. They could not 
well do otherwise and thrive in the climate where they have been 
found most numerous. There is a limit, however, to the amount of 
moisture the larvae can stand, for in one instance in the laboratory 
the mortality was about 70 per cent, and it could be attributed to no 
other cause than an excess of water. The duration of the larval 
period is approximately 42 weeks under ordinary conditions, though 
under the most favorable conditions they may develop in 39 or 40 
weeks. Before transforming to pupa the larva prepares a pupal 
cavity or cell by drawing about it all castings and thus surrounding 
itself with more or less of a wall that would be difficult for any insect 
enemy to penetrate. The larva then cuts a hole into the bark and 
transforms to the pupa. During the growth of the larvae in the branch 
