68 



normally aphis feeders, but I found quite a number at Tilbury, 

 which were observed in several instances feeding on the Colorado 

 potato beetle's eggs, devouring them most greedily ; and I can not 

 help thinking that they did nmch of the work in getting rid of the 

 enemy. The eggs of this ladybird were deposited on the potatoes 

 and were sent in, in many instances, as Colorado potato beetle eggs. 

 They certainly present a general rough likeness, but can at once be 

 told by their smaller size and paler yellow hue. The pupae of this 

 beneficial insect also bear a slight resemblance to those of the potato 

 '' bug " and have frequently been sent in as such. They are very 

 much smaller in size, however, and could not be mistaken by an 

 expert. 



AN EXPERIENCE WITH HYDROCYANIC-ACID GAS AS A RIMEDY 

 FOR THE CIGARETTE BEETLE IN DWELLINGS. 



By F. H. Chittenden and F. C. Pratt. 



During the first week of September, 1904:, two persons residing in 

 the northeast section of Washington, D. C, complained of injury 

 to furniture, rugs, and tapestry in their dwelling houses, submitting 

 specimens of the larva and adult of the cigarette beetle {Lasioderma 

 serricorne Fab.) as the cause of their troubles. The first' house- 

 holder was very fearful lest the insects would spread from the only 

 room infested to others, including one containing a valuable library; 

 and the other, a lady, was in an exceedingly nervous condition, 

 brought about through her ineffectual struggles to evict the " bugs " 

 from her domicile. Gasoline, benzine, " black flag," and various 

 other insecticides, including formaldehyde, had been used without 

 avail, as had also red pepper. The insects were believed, and with 

 reason, to have fed and multiplied on the last-mentioned substance. 



As no experiments had hitherto been made with the hydrocyanic- 

 acid gas treatment for this insect, experiments were instituted in the 

 second house. A visit to this house showed injury plainly visible on 

 the upholstered furniture, and the edges of a carpet were frayed. 

 Numbers of beetles and their larva? were observed, the last in cells 

 preparatory to pupation. 



Exj^eriment No. 1. — The gas was used at the usual strength — 1 

 ounce of cyanide of potash to 100 cubic feet of space, the doors and 

 windows being quite securely closed. The exposure was seventeen 

 hours. Upon aerating the following morning many beetles were 

 found apparently dead on the floor and were swept up and kept in 

 a box to ascertain if they might revive. All died, however, and the 

 result was looked upon as satisfactory. 



Exyeriment No. 2. — About two weeks later more adults were 

 noticed about the house, and as they continued to accumulate notice 



