. The clover root-borer (Hylastinus obscurus Marsham). Roots (Botany) Diseases and pests; Hylastinus obscurus; Borers (Insects). Fig. I.—Hylastinus obscurus: Larva or grab—much en larged (original). LIFE There is certainly but one generation annually, though this appears to be long drawn out, and scattering individual larvffi and pupae may be found throughout every month of the year. The finding of eggs as late as September 18 has been reported from Michigan. As a rule, however, the insects pass the winter in the adult stage (fig. 1) within the roots where they developed. During May
. The clover root-borer (Hylastinus obscurus Marsham). Roots (Botany) Diseases and pests; Hylastinus obscurus; Borers (Insects). Fig. I.—Hylastinus obscurus: Larva or grab—much en larged (original). LIFE There is certainly but one generation annually, though this appears to be long drawn out, and scattering individual larvffi and pupae may be found throughout every month of the year. The finding of eggs as late as September 18 has been reported from Michigan. As a rule, however, the insects pass the winter in the adult stage (fig. 1) within the roots where they developed. During May they abandon the old roots and seek out fresh plants or fields in which to lay their eggs. The eggs are mostly de- posited between the middle of May and June 20. The female gouges out a shallow cavity, more often in the crown of the plant, sometimes at the sides of the root even 2 or 3 inches below the crown, and in this places, singly, but not far separated, about half a dozen pale, whitish, elliptical, very minute eggs. These hatch in about a week, and the larvae (fig. 2) for a time feed in the excavation made by the mother, but soon burrow downward into the root, and before the first of August the majority of them have become fully grown and passed into the pupal stage (fig. 3). By October nearly all have become fully developed beetles, but they make no attempt to leave the plant until the following spring. Bach states that the adults fly at Omegnen in March and April, while Eichhoff has observed them near Miilhausen, swarming during the warm afternoons about the middle of Fig. S.—Hylastinus obscurus: Pupa- much enlarged (original).. 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 Webster, F. M. (Francis Marion), 1849-1916; United States. Bureau of Entomology; United States. Dept. of Agriculture. Wa
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