116 



EwiNG (H. E). Studies on the Biology and Control of Chiggers.— 



U.S. Dcpt. Agric, Washington, D.C., Bull. 986, 3rd December 

 1921, 19 pp., 4 figs. [Received 22nd March 1922.] 



After studying Riley's descriptions and figures of Leptus americanus 

 and L. irritans, the author has come to the conclusion that the former 

 is an Erythraeid and not a Trombidiid, and that L. irritans is the 

 larva of a species of Trombidiid, but the characters given by Riley 

 are not even of generic value, and it appears doubtful whether it will 

 ever be known with certainty what species his irritans is. The author 

 is also unable to correlate these species of Riley's with the two species 

 that are familiar to him. One of these is found in New Jersey, Mary- 

 land, Columbia, Virginia and south-eastern Iowa, and the other is 

 a closely related species in the northern and western United States, 

 which has been studied by Howard [R.A.E., A, vii, 327]. 



Notes are given on the seasonal history of these mites, their local 

 distribution and habits, their hosts, the injury caused and their relation 

 to disease. Though the only disease known to be transmitted by 

 these Acarids is Japanese river fever, the author predicts that they 

 will be found responsible for the carriage of others. 



Man may protect himself from them by means of suitable clothing 

 on the lower limbs, and by applying repellents, such as sulphur, either 

 directly on the skin or on the undergarments, which should be of 

 closely woven cloth and should fit tightly. Topped shoes or boots 

 should be worn. 



Infested, fields may be rendered free by cultivation or cleaning away 

 rough growth. Cattle or sheep are also valuable in destroying the 

 mites. Wild blackberry or dewberry bushes often harbour them. 

 On lawns they automatically disappear, and fields may be dusted 

 with 50 lb. sulphur to every acre. Larvae on the body may be killed 

 by applying acaricides, such as thick lathers of soap, any of the lighter 

 oils, sulphur ointment or commercial alcohol — the latter should be 

 applied freely, and the application repeated two or three times. 

 Palliatives recommended are a saturated alcoholic solution of salicylic 

 acid, with a little olive oil added, ammonia, cooking soda, dilute 

 solution of iodine, camphor and alcohol. 



Johnson (W. T.). Exterminating Poultry Lice. — Bi-Mthly. Bull. 

 Western Washington Expt. Sta., Puyallup, Wash., ix, no. 7, 

 March 1922, pp. 114-117, 9 figs. 



A description is given of dipping and dusting poultry in sodium 

 fluoride for the extermination of lice [Mallophaga]. The dipping 

 method consists of a lukewarm solution of |-1 oz. sodium fluoride 

 to 1 U.S. gal. water ; this should not be applied in cold weather. The 

 dusting method consists in applying a pinch of the drug on the skin 

 and feathers of various parts of the body. One pound of the powder 

 should be sufficient to treat 100 fowls, and one treatment is effective. 

 Poultry will not remain permanently free, although if they are 

 thoroughly treated reinfestation does not take place very quickly. 

 Sodium fluoride does not destroy lice that are blood-suckers [Anoplura], 

 and should not be used against lice on cattle and pigs. The solution 

 should not be left in metal containers, as it corrodes them, and 

 fowls should not be allowed to drink it. 



