48 



H3T)odenna lineata, the ox-warble — Larvae form more or less 

 conspicuous lumps under the skin of the backs of cattle during the 

 latter part of winter or early spring. Adult fly about 12 mm. long, 

 very hairy, and somewhat resembles a small black bee in appearance. 

 Though unable to bite, cattle have a great fear of them. Deposit 

 eggs, throughout the summer, on the hairs of cattle and young larvae 

 are taken up by licking and penetrating the walls of the oesophagus, 

 migrate through the tissues to reach the subcutaneous tissue of the 

 back of the host. In spring or early summer the grub emerges, 

 pupates in the ground and adults emerge in about a month. Studies 

 of Carpenter, '07, indicate that larvae may possibly enter skin 

 directly, but this is not normal method. Estimated that loss by 

 injury to hides, decrease in milk and beef, and lessened vitality reaches 

 over $90,000,000 annually in this country. Preventive measures, 

 such as protection of cattle from attacks of the fly, hardly feasible. 

 Much may be accomplished by removal of the gruljs, by pressure, 

 during late winter and spring. 



Oestrus ovis, the sheep bot-fly or head maggot — Adults somewhat 

 resembling "an overgrown house-fly" appear in June and July and 

 deposit living larvse, or eggs ready to hatch, in nostrils of sheep. 

 Larvae pass into frontal sinus and horns, causing disease known as 

 "staggers". Mature in about ten months and are expelled by sneez- 

 ing of the host, pupate in the ground, and adults emerge in forty to 

 fifty days. Preventive measures, such as smearing noses of sheep 

 with oil or tar not of demonstrated value. Substances to make the 

 sheep sneeze and thus expel the larvse no more efficient than the 

 irritation caused by the larvse itself. Removal of immature grubs 

 by surgical treatment worth while in case of valuable animals. 



Family MtJSCIDAE, including the flesh flies, house-flies, horn- 

 flies, and many others — By some writers considered a superfamily, 

 with many families. 



Musca domestica, the common house-fly — 90 per cent of the flies 

 found in houses being of this species. Detailed description unneces- 

 sary, but it should be emphasized that the mouth-parts are adapted 

 solely for sucking and lapping. Breeds primarily in horse manure, 

 but also in decaying vegetation, garbage, and human feces. 120-|- 

 eggs in a batch and may deposit as many as four batches. Larvse 

 known as maggots. Entire life cycle in hot weather may be under- 

 gone in ten days. Always a pest, the house-fly is now known to be 



