In 1898 I published1 a brief account of certain amœbulæ and flagellulæ found by me during the previous year in mosquitoes near and in Ootacamund, India. Similar parasites were frequently observed by me subsequently in various species of Culicina, especially in C. fatigans Wiedemann, and once in an Anophelina. Since then what appear to be the same, or at least closely allied, organisms have been described as occurring in Anophelina by Chatterjee, Stephens and Christophers, and L´ger, the last of whom named them Chrithidia fasciculata. Their habitat appears to be principally the intestinal cavity of the larva, pupa and imago. Many of them (as still well shown in an unstained preparation of my own made in Calcutta in 1899) have a considerable resemblance to trypanosomes—a resemblance which appears to be further suggested by the stained preparations of Léger, Christophers, and Stephens.