94 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



shaker can. Examinations two days after dusting and subsequently 

 failed to reveal the presence of adults or young, thus indicating complete 

 destruction. Three other infested dogs were dusted with much smaller 

 amounts and all lice and eggs killed. The minimum amount tried 

 on the above hosts was about two grams of a mixture of derris and com 

 starch (one to three). 



Preliminary Tests With Derris Against Larvae of Hypoderma 



lineatum 



A preliminary test of the use of an ointment consisting of one part 

 derris to two parts vaseline applied to the holes of warbles in the backs 

 of cattle indicates that this ointment is as effective as any other material 

 used in this way. Five days after treatment all grubs were found to 

 have been killed and the condition of the cysts was very satisfactory. 

 A wash consisting of one pound derris, four ounces soap and one gallon 

 water applied once with a brush to the backs of infested cattle killed 

 practically all grubs. 



Use of Derris Against Fleas 



Results from the use of derris against dog and cat fleas were surprising 

 and extremely gratifying. A series of tests were carried out by Mr. 

 H. P. Wood in a dog and cat hospital in Dallas. Dr. Allen Foster, 

 the proprietor, very kindly cooperated in this work. Both dog and 

 cat fleas {Ctenocephalus cams and Ct. Jelis) were present. 



In the first test which was begun Oct. 28, 1918, three dogs were given 

 a thorough treatment with undiluted derris with a dust gun. On the 

 following day a single living flea was observed. On repeated examina- 

 tions extending up to Nov. 10th no more living fleas were found despite 

 the fact the dogs were associated with other infested individuals. 



Four dogs of three breeds were given a thorough but rather light 

 dusting with derris undiluted and no live fleas were found on them two 

 days later. 



A series of tests with several breeds of dogs indicated that the minimum 

 dosage necessar}^ to completely destroy all fleas was .87 grams of a 

 mixture of equal parts derris and com starch per animal. When the 

 quantity of derris was reduced to .2 grams one hundred percent kill 

 was not realized. 



Following these preliminary experiments derris and com starch in 

 the proportion of 1 to 3 was applied to all of the animals in the hospital 

 at the time — 48 dogs and 9 cats. The material was put on along the 

 back and neck of each anim.al with the thumb and finger. An average 

 of slightly less than two grams per animal was applied. These animals 

 were treated on Dec. 4 and subsequent examinations up to Dec. 10 

 showed no living fleas. 



