. Flies in relation to disease: bloodsucking flies. Flies; Flies as carriers of disease; Diptera. xvi] REPRODUCTION 267 The pregnant flies are liable to certain accidents of gestation, for in captivity they frequently abort after being disturbed. Sometimes the larva pupates whilst still within the uterus, and in this case both the mother and its offspring invariably perish, as the former is unable to feed and the latter cannot emerge from the pupal case. A high degree of humidity is very unfavourable to reproduction, for Roubaud noticed that when flies were exposed to a saturated atmosphere th
. Flies in relation to disease: bloodsucking flies. Flies; Flies as carriers of disease; Diptera. xvi] REPRODUCTION 267 The pregnant flies are liable to certain accidents of gestation, for in captivity they frequently abort after being disturbed. Sometimes the larva pupates whilst still within the uterus, and in this case both the mother and its offspring invariably perish, as the former is unable to feed and the latter cannot emerge from the pupal case. A high degree of humidity is very unfavourable to reproduction, for Roubaud noticed that when flies were exposed to a saturated atmosphere they either aborted or did not develop larvae. These results would explain why the females sometimes avoid the immediate neighbourhood of water, w^hereas the males generally seek the damp places where they require less food. The effect of this difference is to cause that separation of the sexes of the flies, that has been noticed bv manv Fig. 70. Freshly laid of Glossina palpalis shewing the changes in the body form. (After Roubaud.) When the larva is born it is a white cylindrical maggot, with two black protuberances at its posterior extremity. Its dimensions vary from 7 to 7-4 mm. in length by 2-8 to 3-5 mm. in diameter. At first the larva is very active, presenting curious alternate contractions and expansions of its body (Fig. 70) causing it to assume very varied forms. These movements enable the larva to bore its way into any fissures or loose soil, and are peculiar to the members of the genus Glossina. In loose sand the larva usually comes to rest at a depth of about half an inch to an inch and then pupates. The duration of the free larval stage does not exceed an hour to. 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 Hindle, Edward, 1886-. Cambridge, University Press
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishe, booksubjectdiptera
