Microscopical anatomy of larva of cheladonta costulata (Acarina: Trombiculidae) II. Body tegument and digestive system.

The cuticle of gnathosoma of Cheladonta costulata larva consists of a smooth and firm epicuticle and sclerotized procuticle. The cuticle of the idiosoma is elastic. The wall of the digestive system is formed by cells lying on the basal membrane. During the process of sucking, however, the intestinal cells, which were originally spherical, get an appearance of a club reaching up to the lumen of intestine. In a fully engorged larva the intestine appears to be united and fill the major part of body. The lumen of the intestine is filled with eosinophilic granules of various size, among which are minute granules with basophilic tinge. The excretory bladder is located between posterior lobes of the intestine. In an unengorged larva, the excretory bladder is conical and possesses a conspicuous wall of a cellular structure. Its lumen is empty. In a fully engorged larva, the excretory bladder is oval, covered with a thin membrane, and its lumen is filled with guanine crystals.