1910) Reiff — Liparis dispar L. 69 
ON THE RESISTANCE OF GYPSY MOTH EGGS (LIPARIS 
DISPAR L.) TO COLD AND OTHER CONDITIONS. 
By Wiuuram Reirr, Harvarp UNIvVERsItyY.! 
In the “‘Illustrierte Wochenschrift fiir Entomologie,’” Neudamm 
1897, N. Kulagin has published a paper entitled ‘‘Zur Biologie von 
Ocneria dispar in Russland,” in which the author says that a lowering 
of the temperature to —40° R. does not have any injurious effect on 
normally laid eggs of this moth. Eggs which are deprived of their 
protecting wool, however, will be killed by —15° R. (=-182 C.) Con- 
cerning the method of procedure in these experiments, Prof. P. Bach- 
metjew obtained more exact information from N. Kulagin by letters, 
which he includes in the first volume of his well-known “ Experi- 
mentelle Entomologische Studien,” Leipzig, 1901, p. 70. He says in 
this place that Kulagin depilated the eggs and left them for one month 
in a glass dish upon an open balcony. During this time the thermome- 
ter not infrequently reached -15° R. In the spring these eggs did not 
develop, although there were caterpillars hatching from other eggs 
kept upon the same balcony, but which were attached to a piece of 
wood with their hair. The question was left open as to the result of 
leaving eggs covered with hair during the winter in a dish of glass. 
I was induced by these investigations to undertake in October, 1908, 
the following experiment: From dispar egg clusters obtained at 
Forest Hills, Mass., there were selected five clusters so divided that 
each egg cluster was separated into three nearly equal parts. One 
part of each five clusters was attached with good glue to a barky piece 
of wood and the second thirds of each were lightly pasted to the 
bottom of five open glass dishes, while the eggs of the last five thirds 
were entirely depilated and put into five other glass dishes. All three 
series remained constantly at the outside temperature, but protected 
from snow and direct contact with water. Two other egg clusters 
were divided in two nearly equal parts and one part of each cluster was 
put into a rather small wooden box, from which the cover had been 
removed. The eggs of the two remaining parts were depilated entirely 
and then placed separately in two other wooden boxes without covers. 

1 Contributions from the Entomological Laboratory of the Bussey Institution, Harvard 
University. No. 17. 
