Genus Janthinosoma. 125 
One female deposited forty eggs on the Ist of May, some at 
the bottom of the glass containing the water, while others were 
resting upon some fibres of cotton which had accidentally fallen 
into the vessel. Dr. Duprée thinks it altogether likely that the 
eggs, which are deposited singly under normal conditions, rest 
upon floating débris. 
The eggs somewhat resemble in shape those of Stegomyva 
fasciata, though larger. Short spines pointing towards the so- 
called head of the egg are uniformly distributed over the entire 
shell. The egg has a flat and a convex surface, and with the 
latter uppermost presents a distinctly fusiform shape. Unless 
débris floats upon the surface of the water all the eggs sink to 
the bottom, which accounts no doubt for the irregular periods of 
incubation. Of the forty eggs deposited during the night of 
the 30th of April, a few hatched on the 15th of May, others 
hatched on the 30th of May and others on the 10th of June. 
Thus the egg period may last from fifteen to forty days. 
The larvae are active at the surface of the water for the first 
twenty-four hours, after which they move to the bottom when 
disturbed, and can remain there forty-seven minutes. They grow 
rapidly, one hundred and twenty hours being sufficient for their 
development, but the period may be extended to seven days. 
They move by jerks when suddenly disturbed, but usually with 
little motion at an angle of 45 degrees. While at the bottom 
they catch large bundles of Spirogyra, which are broken into 
small pieces as the surface is approached ; the small pieces of food 
are swept into the mouth by the vortices set up by the oral cilia 
‘The pupae are very sensitive. Length of pupal life twenty- 
four hours. 
JANTHINOSOMA POSTICATA. Wiedemann. 
(Mono. Culicid. I., p. 253, 1901.) 
A series of females has been sent me by Dr. St. George Gray 
with the following note: ‘‘The place where I got them (Choe) 
is about 34 miles to the north of Castries, about 7 mile from the 
sea, and very slightly raised above sea-level. They attacked me 
while I was securing some larve from a culvert under the road. 
What I chiefly noticed about these mosquitoes was their large 
size and loud note and the vicious way in which they attacked 
me; most of those that bit on my hands were crushed in trying 
to capture them, for nothing would make them move once they 
