THE BIOLOGY OF CEPHALONOMIA WATERSTONI GAHAN

Abstract

Life history and morphological studies were made on Cephalonomia waterstoni Gahan, a hymenopterous parasite on the larval and pupal stages of the rusty grain beetle, Laemophloeus ferrugineus (Steph.). At 90° F. and 65 to 75% relative humidity the whole life cycle of C. waterstoni is completed within 12 to 13 days. The adult life span of females is about three weeks, while that of males is much shorter. The male, which prior to this work was unknown, can easily be distinguished from the female by its smaller size, its less rectangular-shaped head, and its longer antennae. The first flagellar segments of the males are brownish-black in color while those of the females are yellowish. The ratio of females to males is somewhere near 2:1. The ease with which the parasite C. waterstoni can be reared in large numbers in the laboratory, and its remarkable ability to check infestations of L. ferrugineus under experimental conditions, indicate that this species might be of value in biological control programs for L. ferrugineus in warehouses, mills, and elevators.