April, '06] ENTOMOLOGICAL NEWS. 131 



nearly one- third full of furniture, so that there was not over 

 1,600 cubic feet of air-space to be fumigated. The room was 

 made as tight as practicable and eight ounces of the Solidified 

 Formaldehyde were used, strictly according to directions, in a 

 generator specially designed for using it. The fumigation was 

 begun at nine o'clock a. m., January 30th, 1906, and the room 

 was not opened until the next morning, thus continuing the 

 fumigation for twenty-four hours. As the formaldehyde costs 

 about 35 cents an ounce, it was an expensive operation for a 

 single, medium-sized room. 



Upon opening the room, the formaldehyde fumes were suffi- 

 ciently strong to make one's eyes and nostrils smart, and it 

 was several minutes before I could go into the room comfort- 

 ably to get the insects. 



Although more than the designated amount of Solidified 

 Formaldehyde was used and the fumigation was continued 

 longer than specified, yet it resulted in not killing a single 

 bedbug or cockroach. 



Dr. L. O. Howard writes me that "The Public Health and 

 Marine-Hospital Service report formaldehyde as not possess- 

 ing insecticidal properties against mosquitoes." Also, that 

 Mr. Titus, one of his assistants, knows of an instance where 

 a large number of Lepidopterous pupae in soil were in a small 

 room where formaldehyde gas was generated (strength of the 

 gas unknown), and from none of these pupae were adults 

 afterwards bred, while from other pupae from the same ma- 

 terial, not in this room, the moths came out in usual numbers. 

 The inference is reasonably plain that the gas killed the 

 pupae, but the evidence is not conclusive, as it was not an ex- 

 periment but simply an accident. 



In 1 901, C. L. Marlatt, of the Bureau of Entomology, re- 

 ported (Bull. 30, New Series, p. 39) some experiments to test 

 the insecticidal value of formaldehyde gas. Some earlier 

 trials had resulted in indicating little value in the gas for kill- 

 ing insects. Then a test was made against the Angoumois 

 grain moth and the bean weevil in stored seeds. The gas was 

 generated to 3 or 4 times the amount necessary for germicide 

 purposes. Only a few of the moths (some that were flying 



