1917] Bishopp and Wood—Experiments with Sodium Fluoride 187 
fested regions to concentrating points from which they were trans- 
shipped to Europe for military purposes may have resulted in 
the establishment of other foci of infestation not now known. 
Increased activity at this time in the shipment of horses from the 
infested territory for use in our own cavalry and for agricultural 
purposes will no doubt give every opportunity for the insect to 
become widely established if some natural agencies do not prevent 
or steps are not taken to destroy the bots before horses are shipped. 
The accompanying map shows the probable present distribution 
of the species in the United States, and indicates the points where 
its presence has been observed by us or recorded by correspondents. 
The comparatively small number of large dots in North Dakota 
is explained by fewer circulars being sent there rather than by a 
smaller number of nose flies. 
PRELIMINARY EXPERIMENTS WITH SODIUM FLU- 
ORIDE AND OTHER INSECTICIDES AGAINST 
BITING AND SUCKING LICE. 
By F. C. Bisoorr and H. P. Woop, 
Bureau of Entomology, U. 5. Department of Agriculture. 
The very satisfactory results secured by the authors with the use 
of sodium fluoride against various species of biting lice (Mallo- 
phaga) on chickens and other domestic fowls' naturally has led 
to inquiry from many sources as to the effect of this compound on 
lice of cattle, horses, and other domestic animals. So it is thought 
advisable at this time to publish a few preliminary notes on the 
results of the use of this material and other insecticides against 
several species of Mallophaga and sucking lice on such hosts. A 
few experiments carried out during 1910 and 1912 indicated that 
the standard arsenical dip usually known as the B. A. I. formula 
(8 Ibs. white arsenic, 24 Ibs. sal soda, 1 gal. pine tar, to 500 gals. 
water) is a very effective insecticide against both the Mallophaga 
and Anoplura. In these tests it was found that one thorough spray- 
ing or dipping of cattle quite heavily infested with biting lice 
(Trichodectes scalaris Nitzsch), and the short-nosed ox louse 
(Hamatopinus eurysternus Nitzsch) completely destroyed them in 
1 See Farmers’ Bulletin No. 801. 
