D. Keilin 
223 
It is highly probable that parasitic ciliates such as Collinia and Lambornella 
undergo a process of multiplication within the cyst-wall, comparable to that 
which is observed to occur in Ichthyophthirius, a parasite of fresh-water fishes, 
and that only those cysts filled with young ciliates, which are capable of 
penetrating the walls of the alimentary canal of the host, are infective when 
ingested by the host. 
That the cysts of Lambornella must pass through some developmental 
phase before they become infective, is supported by Lamborn’s experience, 
in that he obtained successful results in his infection experiments not less than 
three months after the death of the larvae which he used as a source of in¬ 
fection. 
VI. Diagnosis of Lambornella , n.gen. 
Diagnosis: a holotrichous parasitic ciliate. Body elongate oval, length 
50 fx to 70/x, maximum width 20/a to 30/z. Ciliation dense. Cylostome small 
lozenge-shaped. Macronucleus spherical, 10/x to 12/x in diameter; micronucleus 
2/z to 3p in diameter, lying in a peripheral depression of the macronucleus. 
Protoplasm granular, with few basophil vacuoles. Multiplication takes place 
by simple transverse fission into two equal parts. Cysts hemispherical, *30^ 
to 40/x in diameter, 20/x high, transparent and structureless, attached to the 
host’s cuticle. 
One species known: 
Lambornella stegomyiae, n.sp. 
Diagnosis: as that of the genus. 
Habitat: the body-cavity and gills of Stegomyia scutellaris Walker (Diptera, 
Nematocera, Culicidae). 
Description based on material collected by Dr W. A. Lamborn at Kuala 
Lumpur, Federated Malay States. 
VII. Appendix. 
(a) The Ciliate Parasites of Insects. 
The only example of a ciliate, parasitic in the alimentary canal of insects, 
which has been recorded hitherto, is Nyctotherus, the hosts of which are adults 
of Blatta, Gryllotalpa, and Hydrophilus , and the larva of Oryctes (see Biitschli, 
1899, p. 1721). 
To the best of my knowledge, Lambornella stegomyiae is the first and only 
instance of a ciliate parasitic in the body-cavity of an Insect. 
(b) The Ciliate Parasites of Arthrojoods in general. 
It is a matter of some surprise to find how few ciliate parasites of Arthro¬ 
pods are known: I append the following list: 
1. Anophrys maggi Cattaneo, parasitic in the blood of Carcinus maenas. 
The species is very insufficiently described. 
