DISPOSAL OF EGGS 143 
deposited in the water and surrounded by a gelatinous substance. Busck found 
about twenty-five of these eggs united in an ovate gelatinous mass, each egg 
surrounded by its own spherical gelatinous envelope and supplied with an air- 
bubble which helped to keep the mass afloat. Mr. Jennings has since repeated 
this observation. The gelatinous matter furnished the first food to the newly 
hatched larvee. 
So far Joblotia digitatus stands unique, not only among the members of the 
genus, but in the entire tribe of Sabethini, by depositing its eggs in a raft. Its 
raft is a type entirely distinct from those previously described. It is flat and 
circular in outline, instead of elongate and concave as in the egg-boats of Culex. 
Anopheles deposits its eggs separately in small numbers, upon the surface of 
the water. The eggs lie upon their sides and are kept afloat by a peculiar struc- 
ture, a partial envelope which is more or less expanded, particularly along the 
median portion of the egg. This hydrostatic organ is variously shaped and de- 
veloped in the different species of Anopheles. In one case, Anopheles turkhuds 
of India, this apparatus is nearly obsolete and the only trace remaining is a 
small rudiment concentrated near the larger end. In a remarkable Brazilian 
anopheline, Chagasia fajardot, the hydrostatic apparatus reaches a remarkable 
development, completely surrounding the egg and forming a series of longi- 
tudinal, remarkably constructed, air-chambers. 
So far as we are aware the eggs of all Anopheles are provided with the hydro- 
static organ and are normally laid upon the water. The eggs of such a large 
proportion of the species are now known that we can expect no exceptions. The 
eggs of Anopheles turkhudi and Chagasia fajardot, just described, probably rep- 
resent the two extremes of modification of the hydrostatic organ. Recently H. I. 
Cazeneuve claims to have found that in northern China Anopheles pass the 
winter in the egg-state, the eggs being frozen into the mud and hatching when 
thawed out. The observation evidently is based on an error in determination. 
Cazeneuve has undoubtedly taken the males of certain species of Aédes (which 
agree exactly in habits with his observations) for Anopheles on account of their 
long palpi. This is the more excusable as several famous entomologists, in their 
systematic work, have fallen into the same error and have described males of 
culicines as Anopheles. 
The eggs of Bancroftia signifer are laid singly upon their sides, at the margin 
of the water. These eggs are remarkable in that they are fastened down by a 
gelatinous covering which extends all around them in the form of a broad, 
curiously sculptured, rim. Megarhinus lays its eggs singly upon the water. 
Goeldi found the egg-shells of Megarhinus hemorrhoidalis floating separately 
upon the water in little groups of from four to six and this has given rise to the 
statement that the eggs are laid in chains. Green, in Ceylon, has obtained the 
eggs of Megarhinus immisericors from a confined female and found that they 
were scattered singly over the surface of the water. The eggs are regularly oval 
and their surface is closely studded with spinose tubercles which hold the air 
between them and keep the egg afloat. “ The actual operation of egg-laying was 
not seen, but the female was observed jerking itself up and down in the air just 
above the water, and it seems probable that the eggs were shed at that time.” 
