Histological structure of the food canal in the head of adult Nematocera (Diptera): 2. Culicomorpha

摘要

All the species of Culicomorpha have well-developed cibarial pump. The ancestral type of the pharynx is supposed to be present in Dixa (Culicoidea). It is characterized by sclerotized triradiate pharynx, devoid of intrinsic constrictor muscles, perfect development of anterior and posterior pharyngeal dilators, and well-developed system of sphincters. In Culicidae, the posterior pharyngeal pump is hypertrophied and the anterior one is greatly reduced. Representatives of Chironomoidea have a highly variable structure of pharyngeal apparatus. The pharynx of biting midges and blacktlies resembles that of Dixa and Chaoborus. In Thaumalea, and especially in Chironomus, it has weakly developed dilators, a less sclerotized pharyngeal intima, folded epithelium, and intrinsic circular muscle fibers, whose activity reduces the pharynx lumen.