30 
Protozoa in Triclioptera 
alcohol and staining with Delafield’s haematoxylin was found the most 
satisfactory method. Irou-haematoxylin was also successful ; and pro¬ 
longed staining with Giemsa’s stain, followed by rapid dehydration and 
clearing, was useful. 
Description of the Parasites. 
(a) Embadomonas agilis, nov. gen. et nov. sp. 
This interesting new flagellate was found in about 60% of the 
trichopterid larvae examined by me. I never came across it in any of 
the pupae, but on one occasion I found two individuals in the intestine 
of an adult fly. 
The body of the parasite varies from 8 yu. to 14yu. in length, with 
an average maximum breadth of 4'5 g. It is of definite slipper shape, 
with the broadest portion about half-way between the middle and the 
posterior end ; thence it tapers ba'ck abruptly into a well-defined point 
(PI. Ill, figs. 1 and 2). The anterior end is rounded, very flexible, 
and usually bent back at a considerable angle to the long axis of the 
body, forming, as it were, a heel to the slipper. (See PI. Ill, fig. 3.) 
Very striking is the large cytostome, which extends from about 2 g from 
the anterior end to a point almost half-way along the body : its posterior 
border is often produced into a sort of lip. To carry out the slipper 
simile, we should compare the cytostome to the opening into which the 
foot would be thrust. 
There is only one slender flagellum. It arises from a highly 
refractive point at the anterior margin of the cytostome, and is about 
three-quarters the length of the body. It describes a wide spiral 
movement, by means of which the flagellate progresses, rotating with 
great rapidity round its long axis. The backward inclination of the 
anterior end of the body leaves the cytostome facing almost directly 
forward as the animal swims, and bacteria of relatively large size are 
swept into it in the curi-ent produced by the flagellum. It is not 
unusual to see an Embadomonas swimming about with a long bacillus 
sticking out of its cytostome, which gives it rather a rakish appearance. 
In preparations stained with iron-haeraatoxylin the nucleus appears 
as a diffuse, dark-staining area occupying all the anterior region above 
the cytostome (PI. Ill, figs. 1—3). Well differentiated specimens 
show a number of dark chromatin masses in a somewhat lighter back¬ 
ground. The lateral limits of the nucleus are not definite. Often it is 
