192 Rev. G. A. Crawshay on the 
The beetle deposits her eggs in the bark, in numbers varying from 
a single one to batches of five or six in the same spot. She then 
moves on to another spot. I have not found more than six ova 
together. 
These are put away under the plates, the beetle backing in as far 
as she can and then extending her ovipositor a considerable distance 
further to the junction of the plates with the surface of the bark 
from which they are peeling. Or they are inserted in any convenient 
fissure in the tender bark. 
Where this is superficial and the whole of the ovipositor 
is not buried, the operation may be closely watched without 
the beetle being disturbed. 
I have observed the ova, under the lens, passing, one by 
one, down the ovipositor, forced, a small distance at a time, 
with a fluctuating motion. 
By dissection I have found a healthy 2 to contain as many as 
130 well-formed ova. 
A © confined in a glass jar scattered about 30 ova in the wood- 
dust at the bottom of the jar, and on being supplied with a piece of 
bark, laid about 70 more in it before she died. 
I have watched oviposition in the wild state once only, 
when I came on a solitary ? on a newly-sawn strip of larch 
ovipositing on the narrow edge of bark in close company 
with Strex gigas, who was occupied in the same way. 
In confinement, Zetropiwm has laid on a very small 
piece of bark held in my fingers and watched under the 
lens. They will also, in confinement, oviposit on dead and 
exhausted bark which could not support life in the larve. 
The earliest date I have known oviposition take place 
under almost natural conditions was on May 17th, in the 
case of imagos which had emerged prematurely from a log 
that had stood out of doors in a warm aspect. 
Under ordinary conditions they lay early in June and onwards for 
a month. Under abnormal conditions I have obtained ova as late as 
the first week in September 1906, from a second brood reared out of 
doors. 
These autumn-emerged beetles, reared under such abnormal 
conditions as above mentioned, did not lay so freely as the June 
broods, as a rule, and many of the ova did not contain a healthy 
embryo, but shrivelled up in a few days. 
