Larval Chaetotaxy and Notes on the Biology of Toxorhynchites rutilus septentrionalis (Diptera: Culicidae)

The thoracic chaetotaxy of Toxorhynchites rutilus septentrionalis (Dyar and Knab) is described and figured for all instars, and the abdominal chaetotaxy is more briefly discussed. Both larger, subplumose and smaller, nonplumose hairs are present. During metamorphosis there is a reduction in the total number of stout, subplumose hairs despite the gain of 2 such hairs in the third instar, because other stout hairs are reduced to fine, sparsely branched, or simple hairs. Each of the first 5 abdominal segments gains 1 stout hair in the second instar. Vestigial spiracles were noted on the sides of the body. Recognition characters of each larval instar are explained. Females lay eggs singly while in flight. A tree hole found at Macon, Georgia, August 24, 1944, yielded 343 eggs during the remainder of that season, and 2864 eggs during the season of 1945. Embryonic and postembryonic development of the first-instar larvae are described. Mature larvae overwinter, and are very resistant to starvation and desiccation.