Determination of Larval lnstars of the Hickory Shuckworm, Laspeyresia caryana1

Identification of instars is necessary in reporting and explaining phenomena associated with immature insects, in screening insecticides, in timing applications of insecticides, and in working with larvae in the laboratory. The recognition of larval instars also has special application as an index of larval growth (Bean and Batzer 1957) and, therefore, provides a diagnostic tool useful in the evaluation of the development of larvae fed an artificial diet. The width of head capsules has been shown on numerous occasions to provide data from which larval instars can be recognized.