325 
Being unable to procure living animals for experiment, we 
must restrict ourselves to remark, that we are, at this moment, 
quite unable to understand the significance of the bladders. Most 
"probably they have some relation to the peculiar respiratory pro- 
Cess; 
It is of some interest to remember, that the Mansonia-larvæ 
air in the intercellular rooms of the plants. According to H. D. K. 
(1917 p. 894), the larvæ of the genus Aédeomyia (A. squamipennis 
and catasticta) are to be found in shallow ponds covered with 
the water-plant Pistia "from which they probably derive their 
Supply of air although their habits have not been exactly determined." 
They do not come to the surface but hide between the water 
plants. The sipho presents no peculiar structure, being shaped as 
a sipho of a common mosquito-larva; only the tracheæ of the 
tube are said to be rudimentary, On the other hand, the antennæ 
have a very peculiar appearance in comparison with those of the 
other mosquito-larvæ, being strongly curved, inflated hollow, with 
a stout, spinose digit on the tip. H. D. K. (1917 p. 898) suppose, 
that these inflated antennæ may play some part in the respiratory 
process. 
Pupa and Eggs. 
Owing to the peculiar misfortune, that the pond was dried up, 
I was unable to find the other stadia: the pupa and the eggs. The 
Pupa is known in the cases of M. tilillans (H. D. K. 1915 p. 519 
—520), and M. uniformis (Theobald 1903 p. 270). 
The pupæ resemble the common mosquito-pupæ, but differ 
from these in their siphos being very long and "the orifice furn- 
ished with a flap on the outer side half as long as the tube with 
lateral membrane on each side not quite reaching tip". It has been 
presumed, that nor the pupæ come to the surface but remain 
Submersed, attached to aquatic plants by their respiratory siphos, 
the chitinous spine on the top of the trumpets being used as a 
piercing organ. The peculiar hairs on the first abdominal segment, 
used by most Culicid-pupæ as supporting organs in relation to 
the surface-film, are wanting in Mansonia. As far as I am aware, 
nobody has hitherto found the pupa attached to plants, but owing 
