Abstract
Termites of the genus Zootermopsis have been used in many of the studies of cellulose digestion in the Isoptera. These termites are large, easy to handle, and abundant. The two species which have been used, nevadensis and angusticollis, are similar in habits and appearance but can be distinguished in most cases on the basis of the characteristics described by Sumner (1933). They show an overlapping distribution (Chap. 24 in Kofoid et al, 1934) and according to Kirby (1932) they contain the same species of cellulose-digesting protozoa. These are the large hypermastigote flagellates Trichonympha collaris, T. campanula, and T. spkaerica, and the smaller polymastigote, Trichomas termopsidis.