. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 46 THE GRAPE KOOT-WORM. on a large scale, so that variations would be minimized and the final averages would represent approximately normal conditions. The numerous separate experiments have involved the handling of a large bulk of rearing material, which, together with the simulation of nor- mal conditions, has to some extent necessitated special rearing devices and methods of handling. The experiments have been con-. FiG. 20.—Earthen pot with glass cylinder used in rearing the grape root-worm. (Original.) ducte
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 46 THE GRAPE KOOT-WORM. on a large scale, so that variations would be minimized and the final averages would represent approximately normal conditions. The numerous separate experiments have involved the handling of a large bulk of rearing material, which, together with the simulation of nor- mal conditions, has to some extent necessitated special rearing devices and methods of handling. The experiments have been con-. FiG. 20.—Earthen pot with glass cylinder used in rearing the grape root-worm. (Original.) ducted either in the field or under an open breeding shelter, a portion of which is shown in figure 18. This consisted of a temporary struc- ture of light wooden framework covered with waterproof canvas. Most of the rearing material was obtained in the spring, some time previous to the transformation of the larvae. During the past two years of the investigation the insects were to some extent reared. 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 United States. Bureau of Entomology. Washington : G. P. O.
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