. Agricultural zoology. Zoology. INSECTS. 185 green, and after the first moult, dark green to black. Ventral side slate grey. Head shining black. Twelve broad body segments, upon which are many wrinkles of the skin. The sluggish adult is found, during May or August, upon kohl rabi and turnips, mustard and charlock, with its wings folded together. The female, by means of her ovipositor, saws small holes in the margin or under side of the leaf, and lays her eggs in these. The larvse are hatched in from four to six days, and they undergo four moults. The presence of the larvae can be detected by
. Agricultural zoology. Zoology. INSECTS. 185 green, and after the first moult, dark green to black. Ventral side slate grey. Head shining black. Twelve broad body segments, upon which are many wrinkles of the skin. The sluggish adult is found, during May or August, upon kohl rabi and turnips, mustard and charlock, with its wings folded together. The female, by means of her ovipositor, saws small holes in the margin or under side of the leaf, and lays her eggs in these. The larvse are hatched in from four to six days, and they undergo four moults. The presence of the larvae can be detected by their cast skins, which remain sticking to the leaves even when the animals. Fig. 91.—The Turnip Saw-fly (^Athalia spinarvm) : adult female and two caterpillars. themselves, which are often found rolled up on the under sides of the leaves, cannot be seen. The enemy is also known by its way of feeding, for the larvae keep on the surfaces of the leaves (upper or under surface) and eat out longish holes. As soon as these have reached a certain size, other parts of the leaves or other leaves are attacked. When the larvae are numerous the holes continually increase in number until only the leaf-ribs are left. The mature larvae creep into the soil to a depth of from two-fifths to four-fifths of an inch, and spin a small cocoon. The saw-fly emerges either the same or the following year. These insects may therefore appear in May or in August, but in many cases they are seen at only one of these times, either the summer or autumn turnips being attacked, as the case may be. Fowls and ducks willingly eat the larvae, and, provided they. 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 Bos, Jan Ritzema, 1850-1928; Ainsworth Davis, J. R. (James Richard), 1861-1934. London, Chapman & Hall, Ld.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1894
