. Parasites and parasitosis of the domestic animals : the zoo?logy and control of the animal parasites and the pathogenesis and treatment of parasitic diseases . Domestic animals. 4*2 PARASITES OF THE DOMESTIC ANIMALS this species of clustering about the base of the horn, though this only occurs when they are quite abundant. Their purpose in collecting here seems to be for rest in a location where they are not liable to be dis- turbed. There is a somewhat prevalent belief that the flies damage the horn by eating into it, depositing eggs, and developing maggots which may penetrate to deeper str
. Parasites and parasitosis of the domestic animals : the zoo?logy and control of the animal parasites and the pathogenesis and treatment of parasitic diseases . Domestic animals. 4*2 PARASITES OF THE DOMESTIC ANIMALS this species of clustering about the base of the horn, though this only occurs when they are quite abundant. Their purpose in collecting here seems to be for rest in a location where they are not liable to be dis- turbed. There is a somewhat prevalent belief that the flies damage the horn by eating into it, depositing eggs, and developing maggots which may penetrate to deeper structures, etc. This is a popular error for which there is no foundation, for, beyond "fly specking," it has not been observed that the flies do any injury to the horn. Field study will show that this insect assumes two characteristic posi- tions. In the resting position, as they are found when upon the Fig. 23.—Lyperosia irritans: a, egg; b, larva; c, puparium; d, adult in biting position—all enlarged (after Osborn, from Riley and Howard, Bui. No. 5, Bu- reau of Entomology, Dept. of Agr.). the wings are held nearly flat down the back, overlapping at their bases and moderately diverging at their tips. The proboscis is extended for- ward, and the legs are not widely spread. When active and feeding, on thfe other hand, the wings are slightly elevated and held almost at right angles to the body, while the legs are spread. The proboscis is nearly perpendicular in position, and penetrates the skin of the animal at- tacked. To secure this position it works its way to the skin, and is usually observed more or less covered by the hairs. In damp, rainy weather they may be noticed as particularly abundant beneath the hairs of the ventral surface of the body. Effect.—Horn flies appear early in May and become most abundant in July and August. With the coming of cold weather they Please note that these images are extracted from scanned page images that may
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectdomesti, bookyear1920
