. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. LIFE HISTORY OF BLACKFLIES 479 an inch) in length and the largest of them scarcely exceed one- fifth of an inch. Life History. â Unlike the mosquitoes and midges, blackflies breed in running water and few streams flow too swiftly for them. The eggs are laid in large masses, up to many thousands in number, by a number of females. The eggs (Fig. 221 A), which are elliptical and yellowish and have a peculiar slimy coat- ing, are deposited by some spe- cies on leaves or blades of grass which are occasionall
. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. LIFE HISTORY OF BLACKFLIES 479 an inch) in length and the largest of them scarcely exceed one- fifth of an inch. Life History. â Unlike the mosquitoes and midges, blackflies breed in running water and few streams flow too swiftly for them. The eggs are laid in large masses, up to many thousands in number, by a number of females. The eggs (Fig. 221 A), which are elliptical and yellowish and have a peculiar slimy coat- ing, are deposited by some spe- cies on leaves or blades of grass which are occasionally licked by running water, the weight of the eggs sufficing to submerge them; other species dart into the water and deposit directly on the slimy surfaces of sub- merged stones or twigs. The author found a favorite breed- ing place of the blackflies in the woods of Northern Ontario (species undetermined) to be on the slimy boards of old lumber chutes over which water was constantly flowing. It requires at least a week for the eggs to hatch. The larva (Fig. 221B) as soon as hatched attaches itself by a enlarged, not drawn to same scale; , , . 1 !â ,1 ^i^- g-i ^113,1 gills; ant., antenna; dev. g. sucker at the posterior end of the a., developing gill filaments of pupa; body to a stone or other sub- S- ^-^ gi" filaments; m. f., mouth fans; . , . , p. c, wallpocket-like pupal ease; post. merged object. As expressed g., posterior sucker. (A, after Meczni- by Alcock, " one of the most ^°y fâ¢â¢ Jobbins-Pomeroy, others , , ⢠. ⢠. , â¢, 1 !⢠, 1 after Jobbins-Pomeroy.) characteristic attitudes of the larva is to sit upright on the end of its tail, â to use the lan- guage of the poets of the daily press, â with its mouth fans standing out from its head like a pair of shaggy ; The " mouth fans," which are very dehcate and elegant, are used for sweeping microscopic particles into the mouth as they are brought by the running water. The s
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