. Sanitary entomology; the entomology of disease, hygiene and sanitation. nute forms WHAT WE SHOULD KNOW ABOUT MOSQUITO BIOLOGY 269 of plant and animal life in the water, although certain species arepredaceous, and some are scavengers upon the dead animals and insectlife in their habitat. The larvae of mosquitoes are very peculiarly constructed. The mouthis furnished with tufts of filaments which are constantly in vibration. Thehead is large, the antennse long, the thorax somewhat swollen, and theabdomen slender. The sides of the body arc furnished with stiff the next to the last
. Sanitary entomology; the entomology of disease, hygiene and sanitation. nute forms WHAT WE SHOULD KNOW ABOUT MOSQUITO BIOLOGY 269 of plant and animal life in the water, although certain species arepredaceous, and some are scavengers upon the dead animals and insectlife in their habitat. The larvae of mosquitoes are very peculiarly constructed. The mouthis furnished with tufts of filaments which are constantly in vibration. Thehead is large, the antennse long, the thorax somewhat swollen, and theabdomen slender. The sides of the body arc furnished with stiff the next to the last segment there protrudes a long tube nearly asthick as the body itself, and it is this tube that touches the surface ofthe water when the larva rises to breathe. When in this position thelarva ranges downward in various attitudes characteristic of the object of this tube is to get air. At the extremity is a breathinghole, or spiracle, and into it run two main tracheae which extend throughthe body of the insect with many branches which carry air to all parts. Fig. 50.—Larva of the yellow-fever mosquito. Much enlarged. (Howard.) From U. Agr., Office Secy., Cir. 61, fig. 14. of its tissues. The true anal end of the body is furnished with four moreor less developed tracheal gills. When suspended from the surface the wrigglers mouth parts areconstantly in vibration, bringing into its mouth any minute particleswhich float in suspension in the water. It is when the larva extends its breathing tube from the surface ofthe water that it offers the greatest opportunity for control. All effortsto maintain an oil film on the surface of the water are aimed at cloggingup this tube when it comes to the surface, and thus cutting off the airsupply. Occasionally the larva descends to the bottom, jerking its body vio-lently from side to side. The anal tracheal gills undoubtedly assist inthis motion. The larvae are active and move backward through the waterby these jerky movem
Size: 2370px × 1054px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectbenefic, bookyear1921
