SOME PESTS OF OHIO SHEEP 65 



ing sensation produced by lice. Frequently they scratch the in- 

 fested parts with their hind feet or bite at the region infested. 

 Not only do the bites and sharp claws of the lice annoy the sheep 

 but they also affect the smooth pink skin. Animals heavily in- 

 fested with these pests have a roughened dry skin covered with 

 little dry brownish scabs. The wool fibers become loose, probably 

 due to the cutting operations of the mandibles of the insects. Then 

 by continued scratching and gnawing the infested sheep causes the 

 wool to become ragged, short, dry, gnarly and worthless. 



Description of Louse. — The little red-headed sheep louse is so 

 small that it may easily escape detection. It is slightly longer than 

 1-25 of an inch. It is of a pale brownish color and possesses a red- 

 dish head. It commonly lives 

 near the skin on the upper parts 

 of the neck, shoulders, back and 

 thigh, though it may be found on 

 any part of the fleece. Coarse- 

 wooled sheep seem to be more 

 frequently infested. It is prob- 

 able that sheep can only become 

 infested by rubbing against other 11 

 infested sheep or objects which fe~L, 

 these have rubbed against. No %£ 



other host of this louse is as yet S h ee p Louse, Trichodectes 



known. This louse was collected sphaerocephalus, adult and egg, 

 at Wooster, Ohio, November 24, greatly enIarged 



1917, and specimens have been received from Ft. Recovery, Ohio, 

 taken November 21, 1917, and West Cairo, Ohio, January 8, 1917. 

 The life history of this louse is similar to that of other lice. The 

 tiny, pale, white "nits" are glued to the wool fibers. Young lice, 

 similar except in size to the adults, emerge in a short time from the 

 free ends of the "nits". The young shed their skin several times 

 and finally reach maturity. 



Control measures. — The sheep louse may be effectively com- 

 bated at the same time and with the same dips as are recommended 

 for the sheep tick. In the winter, however, dipping is not advis- 

 able. Among the winter remedies that have been suggested may 

 be mentioned fumigation and powder insecticide. Of the powder 

 insecticides sodium fluorid gives the most promise. Sodium flu- 

 orid is a salt belonging to the same group as sodium chloride or 

 table salt. It has recently been demonstrated by Bishopp of the 

 Bureau of Entomology to be 100 percent efficient in combating 



