. A manual of veterinary hygiene. Veterinary hygiene. 426 VETEEINAEY HYGIENE plished by means of a proboscis, the skin being pierced by lancets. The mosquito's hfe-history is briefly as follows: the eggs are laid in a bunch in stagnant pools; from the egg hatches a larva, which, full fed, passes into the pupal stage. Eespiration is accomplished by means of a projection in the case of the larva and two horns in the case of the pupa, which are thrust above the surface of the water. When pupation is over the pupa skin ruptures and the fly emerges. A knowledge of the life-history enables preventiv
. A manual of veterinary hygiene. Veterinary hygiene. 426 VETEEINAEY HYGIENE plished by means of a proboscis, the skin being pierced by lancets. The mosquito's hfe-history is briefly as follows: the eggs are laid in a bunch in stagnant pools; from the egg hatches a larva, which, full fed, passes into the pupal stage. Eespiration is accomplished by means of a projection in the case of the larva and two horns in the case of the pupa, which are thrust above the surface of the water. When pupation is over the pupa skin ruptures and the fly emerges. A knowledge of the life-history enables preventive measures to be adopted for the eradication of mosquitoes in malarial districts. The mosquito gets the malarial organism from man, but with- out the mosquito it cannot be transmitted; therefore, if mosquitoes are destroyed ma- larial fever jeases. To attain this end it is obvious the breeding places of the insect must be attacked; pools should Fig. m.—Tahanus bovis, the Ox ^^ filled in or drained; while Gad-fly; natural size. , . i -n i any larvae in a pool will be suffocated if a film of paraflin oil be allowed to form over the surface. Tahanidce* Gad-flies or Breezeflies, so named from the buzzing sound they make, attack both horses and cattle. The females are blood-suckers, the mouth parts being armed with six lancets for this purpose. This is a very large family, and comprises many species. The best known is Tahanus bovis, or the Ox 'Gad-fly' (Fig. 177), the female of which worries cattle from the end of May to the autumn. It is a big fly as much as an inch in length, with a longitudinal row of whitish triangles along * The description given here of the various flies is taken from a valuable paper,' Insect Pests of Domesticated Aniraals,' by Dr. Stewart MaoDougall, Consulting Entomologist, Highland and Agricultural Society of Scotland. See Transactions, vol. xi., 5th series, 1899. See also 'Plies ^^i^'^°^^Mh'b/^fms^m'°^' ^^'^^. Please note that these images are extract
Size: 1914px × 1305px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyorkwrjenkins
