26 INSECTS INJURIOUS IN 1902. 
of comparatively fresh and drying dung in egg laying, the Horn 
fly visited it for the same purpose only just as it struck the ground, 
it required a quick eye to note their actions before they were back 
again upon the cow. 
Prof. Weed, in Bulletin No. 28 from Mississippi, speaks of 
the noticeable fact of black cattle being more affected than light- 
colored animals, and states that he found a mixture of crude Cot- 
ton Seed oil or fish oil and pine tar mixed, two parts of former 
to every one of the latter, successful. It took him half a minute 

Fig. 34.—Green-bottle Flies ovipositing on dung, enlarged. Original. 
to apply this to each animal, using a large paint brush for the 
purpose. The cost of the application exclusive of labor was three- 
fourths of a cent per head. He claims that the efficacy of this lasts 
for a week or more. 
From another source it is learned that it is practicable to mix 
lime copiously with dung in small stock yards, and perhaps also 
