tet 
With vats equipped like the above, from 75 to 80 per cent of the 
horn flies on the cattle are destroyed.¢ 
Mr. Hunter experimented with a small model of a dipping vat, and 
found that if the splash were received on a slightly curved galvanized- 
iron sheet instead of a board it was considerably more effective in dis- 
tributing the back throw of the water in the form of an efficient spray. 
The arsenical dips used for the cattle tick would have comparatively 
little value for the horn fly except that very likely a good many flies 
might be caught and destroyed by merely being wetted with the dip. 
A similar treat- 
ment has recently 
been the subject of 
experiment in the 
West. Anapparatus 
has been con- 
structed, designed 
more particularly 
for the destruction 
of skin parasites of 
cattle, to supplant 
the old method of 
dipping inavat. It 
has been suggested 
that this apparatus 
will furnish a very 
good means of con- 
trol in the case of 
the horn fly. The 
probabilities are, 
however, from the 
experience with the PLAN : 
horn-fly traps re- Fig. 5.— Ground plan of dipping vat used by Mr.J.J. Welder. (Original.) 
ferred to below, that most of the flies would abandon the cattle at the 
moment of entrance to the cylinder, and its efficiency as a means of 
horn-fly control is very problematical. 
The process consists in driving the animals through a large cylinder 
through the sides of which a powerful gasoline pump causes sprays 
of the insecticide to strike the animals from all quarters and thor- 
oughly wet them. This machine is patented and is sold at a rather 
excessive price. The liquid used is an emulsion of crude petroleum 
SLASH LS04770 
a For further details of the construction of dipping vats see Farmers’ Bulletin 378, 
‘““Methods of Exterminating the Texas Cattle Tick,’’ by H. W. Graybill, Bureau of 
Animal Industry. In the case of the vat there described, to successfully use the 
splashboard it may be necessary to increase the height of the sides of the vat so that 
the splashboards can be placed 4 feet or a little more above the level of the dip. 
(Cir. 115] 
