. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. Fig. 20.—Silk-worms .spotted with pebrine, twice natural size (after Pa teur). Fig. 20 "represents, at twice the natural size, the anterior part of the body of sick worms covered with such spots. In one of the worms, a, they are just becoming visible, and the eye should be aided by a magnify- ing glass to render them distinct; the other, h, shows them farther ad- vanced, easily recognizable with the naked eye, if the worm be examined with a little attention. Finally, Fig. 21 shows one ring spotted with pe- b
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. Fig. 20.—Silk-worms .spotted with pebrine, twice natural size (after Pa teur). Fig. 20 "represents, at twice the natural size, the anterior part of the body of sick worms covered with such spots. In one of the worms, a, they are just becoming visible, and the eye should be aided by a magnify- ing glass to render them distinct; the other, h, shows them farther ad- vanced, easily recognizable with the naked eye, if the worm be examined with a little attention. Finally, Fig. 21 shows one ring spotted with pe- brine, magnified to six diameters. For this cut was chosen a worm bearing two kinds of marks, one with clear-cut edges, the others surrounded with a halo. The first are wounds, the others the true spots belonging to the disease and serv- ing as an indication of its existence, if not al- ways, at least under many circumstances. The halos in question have generally a yellowish tint. They must be observed through a mag- nifying glass to be well ;! These spots disappear with the shedding of the skin at each molt only to reappear again within a few days. Worms bearing them are figured in plate I, A, B, C, and D. In addition to these symptoms it is noticed that the prolegs do not seem to attach themselves easily to objects. In the chrysalis the abdomen is very much swollen and the rings stretched. In a highly-diseased' moth the wings are wrinkled as when they emerge. 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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