Insects and insecticidesA practical manual concerning noxious insects and the methods of preventing their injuries . the spring and early summer one mayoften find along the middle of the backs of cattle,just beneath the skin, a hard lump, usually havingin the center an opening, which sometimes is moreor less of a running sore. These are the warbles,and the lump is caused by the presence of a whitishor grayish maggot of the form represented at a, Early in summer these maggots wriggle outof the warbles, tail foremost, through the openingrepresented at d, and fall to the grou
Insects and insecticidesA practical manual concerning noxious insects and the methods of preventing their injuries . the spring and early summer one mayoften find along the middle of the backs of cattle,just beneath the skin, a hard lump, usually havingin the center an opening, which sometimes is moreor less of a running sore. These are the warbles,and the lump is caused by the presence of a whitishor grayish maggot of the form represented at a, Early in summer these maggots wriggle outof the warbles, tail foremost, through the openingrepresented at d, and fall to the ground, where, un-der such protection as may be at hand, they shorten 260 INSECTS AFFECTING DOMESTIC ANIMALS. for pupation as shown at d, and soon change to thepupa or chrysalis state, represented at e. About amonth later they emerge as adult flies, one of whichis represented, natural size, at a. These flies pair,and the females deposit eggs on the backs of eggs hatch into grubs that work their way intothe skin, where they form the warble cells. Theirmouth parts irritate the flesh, causing an ulceration,. c d Fig. 136. Ox Warble Fly: a, larva; b, pupa; c, fly; d, section of * which not only is distressing to the animal, but in-jures the hide and beef, and, in the case of dairy ani-mals, lessens the quantity of milk produced. The beef beneath these warbles has a peculiar,diseased, sickening appearance, and is commonlycalled licked beef. Such beef always commandsa lower price than that which is unaffected. Remedies.—Every warble maggot destroyed inspring before it escapes to the ground to pupate, INJURING CATTLE. 261 means that one less fly will be present to lay eggsfor the coming brood. This should be carefullyborne in mind, for from it the conclusion is obviousthat if all the maggots present in the backs of cattleof a given neighborhood are killed, the egg-layingbrood of flies will be exterminated, and there will beno injury the next season. There is perhaps
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Keywords: ., bookcentury1800, bookdecade1890, bookidi, booksubjectinsecticides
