. Farm friends and farm foes : a text-book of agricultural science . Agricultural pests; Beneficial insects; Insect pests. THE TWO-WINGED FLIES 127 the adult state, these flies bear a general resemblance to the familiar house fly, although commonly they are some- what smaller and are easily distinguished by experts. The Cabbage Maggot, which is also known as the Radish Maggot, and the Turnip Maggot, is a good example of these insects. The adult flies appear in the cabbage fields when the plants are set out, and deposit their small white eggs about the base of the stalks. A few days later these
. Farm friends and farm foes : a text-book of agricultural science . Agricultural pests; Beneficial insects; Insect pests. THE TWO-WINGED FLIES 127 the adult state, these flies bear a general resemblance to the familiar house fly, although commonly they are some- what smaller and are easily distinguished by experts. The Cabbage Maggot, which is also known as the Radish Maggot, and the Turnip Maggot, is a good example of these insects. The adult flies appear in the cabbage fields when the plants are set out, and deposit their small white eggs about the base of the stalks. A few days later these eggs hatch into tiny, whitish, footless maggots that attack with their rasping mouth parts the outer tissues of the roots. "'^^^^^'~'~' CABBAGE They continue to feed and "^^P MAGGOT grow for three or four weeks, commonly causing the death of the plant on account of the destruction of the sec- ondary roots or of the girdling of the primary root. By the end of this period they become full-grown as larvae and change to pupae. This process of changing to the pupa state in a large proportion of the two-winged flies differs from that of most other insects. The insects are unable to spin cocoons, but they get the protection of an outward covering in this way: The skin, which in most insects is cast off when the larva changes to a pupa, in these maggots gradually hardens and becomes brownish in color. It does not split open any- where, so that it forms a covering to the insect, inside which the latter becomes a pupa after this outer skin, which is now called f he puparium, has hardened. It remains within this puparium about a fortnight when it again changes into. 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 Weed, Clarence Moores, 1864-1947. Boston ; New York : D. C. Heath & Co.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbenefic, bookyear1910
