f 
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+ Re SP GH 0 
Life History of Tetropium gabrielr. 191 
winter, without transforming to pups. ‘To my surprise, on 
August 10th I observed holes in the bark where the first of 
this second brood of the season had emerged, probably a 
few days previously, 7. ¢. within three months of the parent 
stock being put down on these logs. The 9? of this 
second brood coupled and oviposited from August 10th 
onwards, and of the next generation of larvae found in 
this log in October following some had already moulted 
four times. 
I had doubts whether these very small larvze would get 
through the winter, some being so near the surface of the 
bark, but I found them, in March following, after a severe 
winter, at different depths in the bark, in all stages of 
development from the first to fourth moults. 
The above-mentioned rate of development is probably 
the most rapid possible without running the risk of death 
from too high a temperature, for in some of these logs 
where the bark was not of considerable thickness some of 
the larvee had from time to time been scorched to death 
by the fierce July heat to which they had been exposed, 
the bark being very hot to the touch. 
The temperature may, of course, be so high as to impede 
development, for I observe that, subject to a very high 
temperature, the larve which are not killed lie limp, faint 
and prostrate during the warm hours of the day and 
cannot continue feeding. The breathing and fluctuations 
which are normally visible through the delicate transparent 
skin are suspended, and it takes some hours to revive the 
larva and restore its organs to their proper functions. On 
the other hand, after a night’s hard frost in the depth of 
winter, by applying warmth I have caused them to resume 
feeding in a couple of hours. 
The imagos also I have found killed by the heat 
in their cells in the bark. The days when this 
happened were remarkable for their high temperature, 
which ranged between 90°-96° Fahr. in the shade. The 
logs were exposed to the fierce heat of the midday sun. 
I found that to cover the logs with a sheet and water 
occasionally moderated the heat sufficiently to admit of a 
safe though rapid development of the insect in all its stages. 
Oviposition.—I have observed pairs remain coupled for about 
a day and a half and the ? 9 oviposit about a day and a half later, 
both ¢ and @ living on for about three weeks. 
