. The Cattle grubs or ox warbles, their biologies and suggestions for control. Warble flies; Cattle; Insect pests. THE CATTLE GRUBS OR OX WARBLES 59 spiracle to the hole and almost perpendicular to it. Thus the hole in the skin is always near the posterior end of the larva, which may have the anterior portion in any direction. The majority of the cysts have the aperture near the upper side. TOTAL DEVELOPMENTAL PERIOD IN THE BACKS OF CATTLE As with other stages of Hypoderma, there is a variation in the total period required for the development of the larvae from the time the holes are cut throu
. The Cattle grubs or ox warbles, their biologies and suggestions for control. Warble flies; Cattle; Insect pests. THE CATTLE GRUBS OR OX WARBLES 59 spiracle to the hole and almost perpendicular to it. Thus the hole in the skin is always near the posterior end of the larva, which may have the anterior portion in any direction. The majority of the cysts have the aperture near the upper side. TOTAL DEVELOPMENTAL PERIOD IN THE BACKS OF CATTLE As with other stages of Hypoderma, there is a variation in the total period required for the development of the larvae from the time the holes are cut through until the larval growth is completed. The determination of this period with accuracy is of much importance in control and especially in eradication work, since the interval between treatments should be governed by such data. In a large num- ber of cattle of sev- eral breeds warbles of both species were followed through their entire develop- ment in the subder- mal tissue. Owing to the high mor- tality among the larvae, especially when examined re- peatedly to deter- mine molts, etc., only a comparative- ly few records of complete develop- ment were obtained among the hundreds of warbles observed. In order that the duration of the lar- val stages might be determined various individual cattle were observed from the time warbles began to appear until all grubs had made a normal egress. These observations were made as frequently as time would permit, usually once each day. Through practice the touch was developed to a high degree and one could readily detect the first indication of a foreign object under the skin or a minute amount of exudate from a puncture of the skin. In making the examinations a headlight was developed which proved of great value (fig. 28). It consisted of a shortened flash light attached to a head band, and served by two dry cells carried on a belt. The focus was adjusted to permit the observer to use a hand lens. With the younger stages of the larvae in pa
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Keywords: ., bookcentury1900, bookdecade1920, booksubj, booksubjectinsectpests
