Ernest Edward Austen

“ The tip of the proboscis is armed with a complicated series of chitinous teeth and rasps, by means of which the fly is enabled to pierce the skin of its victim; as usual in Diptera the organ is closed on the upper side by the labrum, or upper lip, and contains the hypopharynx or common outlet of the paired salivary glands, which are situated in the abdomen. The proboscis of tsetse-flies is without the paired piercing stilets (mandibles and maxillae) possessed by other blood-sucking Diptera, such as the female horse-flies and mosquitoes. ”

“ It appears, however, that in this respect the habits of the different species show a certain amount of variation; thus, while G. palpalis exhibits an especial fondness for water and haunts more or less dense cover at the water's edge, recent observations in German East Africa show that G. fusca is in no way connected with water, but is much more frequently encountered at a distance from it. ”

“ As a rule tsetse-flies are most active during the warmer hours of the day, but they frequently bite at night, especially by moonlight. The blood-sucking habit is common to both sexes, and the abdomen, being capable of great expansion, is adapted for the periodical ingestion of an abundant food-supply. ”