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the death of so many larvex from disease, he suggested a possible over- 
crowding of the larve. This, it had been his experience, was respon- 
sible frequently for the death of lepidopterous larve where the latter 
were being reared in large numbers. 
Mr. Howard stated that the mortality was not due to overcrowding, 
since only spun-up larvee and pupe were collected, and these were kept 
under normal conditions. The chief cause of death was probably a con- 
tagious disease, the nature of which is now being investigated by the 
Division of Vegetable Physiology and Pathology. As yet no exten- 
sive observations have been made upon the egg-laying of the secondary 
parasites. These parasites, however, were known to be secondary, for 
the reason that their cocoons were found closely attached to or within 
the cocoons of the primary Pimpla parasite, in which cases there was 
ample evidence that the Pimpla larve had been destroyed. When 
these small cocoons of the secondary parasites (Apanteles, Meteorus, 
et al.) were separated and placed in vials, in some cases chalcidids 
appeared, thus affording almost incontrovertible evidence of a tertiary 
parasitism. These tertiary parasites, as a rule, probably lay their eggs 
in cocoons of hymenopterous insects, and the fact of the parasitism 
being tertiary rather than secondary is probably accidental to a large 
degree. 
Mr. Howard then presented the following paper: 
TEMPERATURE EXPERIMENTS AS AFFECTING RECEIVED IDEAS 
ON THE HIBERNATION OF INJURIOUS INSECTS. 
By L. O. Howarp, Washington, D. C. 
It is a well-known fact among agriculturists and horticulturists that 
winter weather of a steady degree of severity is more favorable to 
plant growth than an open winter with alternating freezes and thaws. 
With regard to certain injurious insects it has become an accepted 
idea among economic entomologists that this same principle will hold, 
yet the question comes to all of us from farmers and others with a 
considerable degree of frequency as to whether a given winter which 
has been unusually severe will not have resulted in the destruction of 
injurious insects to such an extent as to promise comparative immunity 
the coming season. We have been obliged, or at least the writer has 
been obliged, to answer such questions theoretically. There has been 
no exact experimentation, so far as he is aware, along this line. It is, 
therefore, with pleasure that he calls attention to the results of recent 
experimentation by Dr. Albert M. Read, of Washington, the manager 
of the cold storage department of the American Security and Trust 
Company, and the same gentleman who conducted the experiments on 
the effect of cold storage upon household insects referred to in a paper 
read by the writer before the last meeting of this association. Dr. 
Read has found in the course of his experiments, which have now 
