Comparative study of mouthparts of four species of Culicoides from Tibet.

Mouthparts of four species of Culicoides from Tibet were studied by light and scanning electron microscopy (SEM). Photomicrographs were made of the mandible, labrum, hypopharynx, lacinia, and the sensory pit of the third palpal segment for each of the four species. Values for eighteen characters of five structures are presented graphically. Mean values for ten of the eighteen characters evaluated were significantly greater for C. circumscriptus and C. mamaensis than for C. maculatus and C. tibetensis. Photomicrographs revealed specific differences in camber and pitch of the fifth mandibular tooth, in size and location of the subapical labral sensillae, in size of the teeth of the hypopharynx, and in size and depth of the palpal sensory pit and number of sensillae per pit.