M. Koidzumi 281 
The chief points of distinction of the two subgenera are as follows: 
I. Pyrsonympha. The body very large, large, or medium sized; piriform, 
club-shaped, or screw-like. The body is twisted and the flagellar cords wind 
round it; some forms being twisted into a screw, but not curled, as a whole, 
into a spiral. The axial filament hangs in the endoplasm, ending freely in it 
at the posterior end. Two species are distinguished: 
(1) P. grandis sp. nov. (in Leucotermes speratus and L. flaviceps). 
(2) P. modesta sp. nov. (in Leucotermes speratus and L. flaviceps). 
II. Dinenympha. The body small and slender; club-shaped or lanceolate. 
Whole body curled into a spiral. The axial filament distinct or indistinct: 
in the former case its posterior end is held fixed at the posterior tip of the 
body. Five species and one doubtful species are distinguished: 
(1) P. (D.) exilis sp. nov. (in Leucotermes speratus and L. flaviceps). 
(2) P. ( D.) rugosa sp. nov. (in Leucotermes speratus). 
(3) P. ( D.) nobilis sp. nov. (in Leucotermes speratus). 
(4) P. ( D.) leidyi sp. nov. (in Leucotermes speratus and L. flaviceps). 
(5) P. ( D .) parva sp. nov. (in Leucotermes speratus and L. flaviceps). 
(6) P. ( D.) porteri sp. nov. (?) (in Leucotermes speratus and L. flaviceps). 
I. Pyrsonympha. 
The organisms belonging to this subgenus vary remarkably in size, and 
their shapes are, moreover, somewhat conspicuously changeable. Thus I 
have been greatly puzzled in determining the exact number of species to which 
our forms are to be referred. As a result of protracted observations, I have 
arrived finally at the conclusion that there are really two sets of forms, each 
set referable to an independent species. Both of these species are common 
in Leucotermes speratus of Japan proper and Leucotermes flaviceps of Formosa. 
(1) Pyrsonympha grandis sp. nov. (Plate XIV, figs. 54-64). 
The forms of this species, like the others of the same subgenus, differ 
from the members of the preceding series in their mode of life in the intestine. 
They do not always live freely in the lumen of the gut, but a large number of 
individuals are found attached to the wall and hanging in the cavity. The 
forms attached to the wall are usually so numerous that they far exceed the 
unattached forms in numbers. They are found closely assembled and hang 
perpendicularly from the intestinal wall, assuming the shape of a club, rather 
long and straight or slightly curved. In individuals living freely in the lumen, 
the body is shortened and thickened, especially at the posterior region, so 
as to assume the shape of a flask, with a rather large body and a somewhat 
slender neck. Frequently the organism is so thickened that the body becomes 
piriform; but sometimes it is rounded anteriorly, so that the body appears 
oval. The same mode of fife was noticed by Porter in the American species. 
According to him, the young forms are found attached to the intestinal wall 
