. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 20 MISCELLANEOUS 0()TT(JN INSECTS. before April 1, the season being" an exceptional!}- eai'l}' one. The egg's had been laid in the hard ground on the edges of tields and in fields uncultivated during the present season. Young of the first instar taken to the laboratoiy on April 23 molted April 25, May 10, May 23, and May 30 and became adult on June 8. The habit of ascending a stalk of corn or weed during the last molts is illustrated in figure 9. It was found exceedingly difiicult to distinguish the differen
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 20 MISCELLANEOUS 0()TT(JN INSECTS. before April 1, the season being" an exceptional!}- eai'l}' one. The egg's had been laid in the hard ground on the edges of tields and in fields uncultivated during the present season. Young of the first instar taken to the laboratoiy on April 23 molted April 25, May 10, May 23, and May 30 and became adult on June 8. The habit of ascending a stalk of corn or weed during the last molts is illustrated in figure 9. It was found exceedingly difiicult to distinguish the different instars by any markings or by the general size of individ- uals, for in both these re- spects different individ- uals vai-y ver}^ greatly. It was found by measur- ing reared specimens, however, that the length of the hind tibite was fairly constant for a given instar, and this proved true of a series subsequently measured. The length of the meta- tibia is as follows: First instar, 3-4 mm.; second instar, 5-0 mm.; third instar, 8-9 mm.; fourth instar, 11-12 mm.; fifth instar, 15-16 ram. These are the measurements of the cast skins, the meas- urements in the case of live or niounted speci- mens being slightly less in each instar. The time of molting varied for dif- ferent individuals and was governed ])y the amount of food available, so that no fixed dates can be given. In 1903, in a local outbreak, the first three stages, mostly the second and third, were found to occur on June 1. The development during these two seasons probably illustrates the extreme dates of early and late develop- ment for this Fig. 9.—M/lanoplus dijfferentiahson corn leaves: adult i:i natural position, upper figure; pupa skin below on right—n itural size (author's illustration).. 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
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Keywords: ., bookcentury1900, bookdecade1900, booksubje, booksubjectentomology
