15 



department of the American Security and Trust Company, of Washing- 

 ton, who had come to consult him about certain insects found in stored 

 woolens, and who, he found, had already begun a series of experiments 

 in just this direction. Dr. Head very obligingly placed at his disposal 

 a well-equipped cold storage experimental closet which he had had 

 constructed for his own work, and further made careful observations 

 himself, with daily notes upon different species which were furnished 

 to him. In addition, he has since placed at the writer's disposal the 

 notes which he has made upon material collected by himself from goods 

 sent in for storage. 



The series of experiments is by no means yet completed, but the 

 results already reached seem to the writer to be of such value as to 

 deserve immediate publicity. It will not be necessary to present the 

 notes in full, but simply the facts so far learned about each sj^ecies 

 experimented with. The writer wishes it distinctly understood that 

 the notes upon which the statements are based have been made solely 

 by Dr. Head, who has entered upon the investigation with an interest 

 not entirely based upon its economic aspects. 



The common clothes moth (Tinea biselliella). — Eggs. — Iiecently 

 laid eggs of this species were sent Dr. Kead May 2 and were immedi- 

 ately placed at a temperature of 37° F. June 1(3 (the temperature in 

 the interim having varied from 34° to 40°) they were taken out for 

 examination and kept for twenty-four hours at a temperature of 78°, 

 No change could be seen, and they were placed back in cold room, where 

 they have since remained- without hatching, at an average temperature 

 of about 34°. 



Adult — Experiments upon adults are necessarily more or less unsat- 

 isfactory, but here is one of interest. One small bundle of rugs (4 feet 

 long and 1 foot in diameter) out of a large consignment which was 

 found to be swarming with moths was saved from the general cleaning 

 and heating, was rolled lightly in burlap, and placed in test room at a 

 temperature of 02° F. June 21, at 4 p. m., the brine was turned on. 

 June 22, 10 a. in., temperature 32°, nearly all of the moths were dead, 

 those alive being at middle of bundle. June 24, temperature 40°, very 

 few were still alive, and those were inactive. June 25, temperature 

 31°, all were dead. 



Larvcv. — None of the experiments made showed that the larvae sub- 

 jected to a continuous low temperature, even reaching to 18°, will die, 

 although larvae kept at from 28° to 18° for a time, then revived by 

 warmth, and then restored to the cold temperature almost invariably 

 died. In fact the survival at a continuous low temperature is shown by 

 the following experiment: 



June 18, 13 larvre were dropped in a bit of woolen goods and placed 

 in cold room at a temperature of 31° F. June 29, 29° to 33°. July 11, 

 28°. Self-registering thermometer showed 18° lowest temperature. 

 All larvae apparently dead. Five taken out and kept in warm room. 



