. Class book of economic entomology, with special reference to the economic insects of the northern United States and Canada. Beneficial insects; Insect pests; Insects; Insects. 366 ECONOMIC ENTOMOLOGY and blisters formed are very irritating, and the disease may spread rapidly. Sheep Scab Mite {Psoroptes communis var. ovis Furst).—This mite burrows under the skin of sheep forming large areas of crust called scabs. From these areas, commonly confined to the neck, back and rump, the wool falls away. The disease is contagious. Each female lays 15-24 eggs which hatch in 2-3 days; the young mites m
. Class book of economic entomology, with special reference to the economic insects of the northern United States and Canada. Beneficial insects; Insect pests; Insects; Insects. 366 ECONOMIC ENTOMOLOGY and blisters formed are very irritating, and the disease may spread rapidly. Sheep Scab Mite {Psoroptes communis var. ovis Furst).—This mite burrows under the skin of sheep forming large areas of crust called scabs. From these areas, commonly confined to the neck, back and rump, the wool falls away. The disease is contagious. Each female lays 15-24 eggs which hatch in 2-3 days; the young mites mature in 15 days. (See Farmers' Bull. 713, U. S. Dept. Agr.) Family Ixodid^ (Ticks) Cattle Tick (Margaropus anmdatus Say).—In the Southern States this tick causes large losses as the agent responsible for the Texas. Fig. 241.—Rocky mountain spotted fever tick {Dermacenior venustus): female; 2, unengorged male. {Year Book, U. S. Dept. Agrlc.) Cattle Fever. It is a dark 8-legged creature. The engorged female drops from cattle to the ground and la}-s its eggs. The young ticks (seed ticks) on hatching crawl up nearby herbage and drop on the backs of cattle as they brush by. Attached to the skin they feed until they become mature. Rocky Mountain Spotted Fever Tick {Dermacentor venustus Banks). —This tick, with others, is able to transmit the so-called "Spotted Fever" of man in the Rocky Mountain states. It is possible that the ground squirrel of the region serves as a reservoir of the virus. The. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lochhead, William, 1864-1927. Philadelphia : Blakiston
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