2 5 8 
The Ohio Naturalist. 
[Vol. VIII, No. 4, 
parthenogenesis from a definitive cell in the formation of which 
the two polars alone are concerned; or even possibly from a 
single polar cell. The lack of fusion of the polars, if such con¬ 
dition exists, may represent either a primitive condition or a 
more recent, parthenogenetic condition. Theoretically, there¬ 
fore, it is possible to have an “x” endosperm generation of two 
different origins, a “2x” endosperm generation of two types 
differing in constitutional structure, and a “3x” endosperm 
generation, but none of these could properly be called an embryo. 
Botanical Garden, Univ. of Zurich, Nov. 25, 1907. 
SOME OBSERVATIONS CONCERNING THE EFFECTS OF 
FREEZING ON INSECT LARVAE * 
James S. Hine. 
It has been known for a long time that some insect larvae can 
withstand low temperatures without being noticeably injured 
thereby. Also that there is great difference among species of 
insects, or in some cases even among the individuals of a single 
species, in regard to the minimum temperature at which life is 
endangered. Economic entomologists have now and then 
made the claim that frosts, especially w r hen they occurred at 
certain seasons, have been important factors in the control of 
injurious species. 
In 1893 while studying the life history and habits of a moth, 
Bellura obliqua, which passes its larval stage in the stems of the 
cat-tail reed, Typha latifolia, I had an opportunity to make 
some observations on larvae of this species which are normally 
found in the reeds throughout the winter. The winter was 
rather severe for the latitude of Columbus where the observations 
were made, and from January 10 to January 20, the temperature 
dropped below zero every night, varying from -2 Fahr. on the 
10th, to -17 on the 17th. Large numbers of the larvae were 
collected during this interval, some during each day, and with 
the specimens some tests were made. Three larvae collected on 
the 14th, were placed in water and placed outside on a porch roof 
during 12 hours the following night when the minimum tem¬ 
perature recorded was -15. The next morning the specimens 
were brought inside and thawed out, after which they were 
taken from the rvater and kept in a tin box at the temperature of 
a living room for about 12 hours. These same larvae received 
the same treatment for six consecutive nights and days, during 
the time withstanding a minimum temperature of -11 on the 
* Read before the Ohio Academy of Science, Nov. 30, 1907. 
