. Sanitary entomology; the entomology of disease, hygiene and sanitation. 29). The posterior upper part of segment 1 is swollen andwith many spines (fig. 29). Each of the following segments (except 2)has a basal, swollen ring, armed with teeth pointing backward, the teethof the front rows are always larger. Beginning with segment 6 the under 150 SANITARY ENTOMOLOGY part of each ring is much broadened and divided transversely by a narrowsmooth space. On segments 5 to 10 there is on each side behind a fusi-form swollen area pressing against the swollen ring of the next segment;this area also has
. Sanitary entomology; the entomology of disease, hygiene and sanitation. 29). The posterior upper part of segment 1 is swollen andwith many spines (fig. 29). Each of the following segments (except 2)has a basal, swollen ring, armed with teeth pointing backward, the teethof the front rows are always larger. Beginning with segment 6 the under 150 SANITARY ENTOMOLOGY part of each ring is much broadened and divided transversely by a narrowsmooth space. On segments 5 to 10 there is on each side behind a fusi-form swollen area pressing against the swollen ring of the next segment;this area also has spines. The tip of the body shows on the dorsal parta great cavity, in the bottom of which are the stigmal plates, each withthree straight slits, those of one sub-parallel to those of the other;there is no button (fig. 30). Behind this cavity is a higli, transverse,spiny crest; and the ventral part of the tip shows an area covered withspines bearing two rather widely separated, prominent, smooth upper edge of the tip shows four small conical Plate IV.—Screw worm injury to a yearling calf. (Biahopp.) The larva of this insect is called the screw-worm, and occurs insores and wounds of domestic animals and also in man. There arevarious records of its presence in the ears and nose, or nasal cavities,of people; in swellings near the nose; in a boil under the arm; under theskin of a child; and in the navel of a child. It is hardly a possiblefactor in intestinal myiasis of man, and most of such recorded casesprobably belonged to some species of Sarcophaga whose larvje are verysimilar in appearance to those of the screw-worm. Sarcophagidae The Sarcophagidae have two great hooks, and the posterior stigmalplates have three slits as in Calliphora erythrocephala and Lucilia seri- COMMON FLIES AND HOW TO TELL THEM APART 151 cata. However, these slits are not directed toward those of the oppositeplate but are sub-parallel to them. The stigmal field is strongly dep
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbenefic, bookyear1921
