TRANSFORMATIONS OF BUFFALO GNATS. 11 
scheme Fab.), is probably erroneous, as the species is very like S. 
venustum in size and structure. It is the opinion of the writer, 
from many observations, that the largest possible number of eggs 
which are deposited at one time by a single female can not exceed 
500. 
The question whether eggs of Simulium can be subjected to desic- 
cation and then hatch after being immersed again in water is of 
interest, as it has been suggested that in the more or less torrential 
streams found in Texas and the Western States, which flow only a 
few months in the year, the eggs might remain in a dry condition 
during the summer and hatch in the fall or spring with the rising 
of the water. For this reason experiments have been made by the 
writer to ascertain whether Simulium eggs, after partial or complete 
desiccation, would hatch on being again placed in water, as is the 
case with some species of mosquitoes. These experiments all showed 
that at Spartanburg, S. C, the contents of freshly laid eggs became 
completely disintegrated after being thoroughly dried, and that when 
the eggs contained embryos, the latter became distorted on the second 
day after removal from the water, and though they were replaced 
in running water after that period the contents of all finally disinte- 
grated without a single egg hatching. 
When eggs are found at any distance above the water line, the 
writer believes investigation will show that a fall in the water level 
has occurred. The great outbreaks of Simulium in the large rivers 
during the early spring are due primarily to the fact that the rising 
water submerges the growth on the banks and that the water either 
rises or remains at the same level throughout that period, thus pre- 
venting desiccation of the eggs. 
THE EGG STAGE. 
The eggs of Simulium are usually rather triangular in shape, with 
the angles broadly rounded. (PI. Ill, figs. 1-5.) The egg of S. 
pictipes (PI. Ill, fig. 6) , however, is more ovoid in shape than that of 
the four other species dealt with in this paper. The shell, which is 
very tough and apparently somewhat chitinous, withstands the action 
of the water for a considerable period without disintegrating, and 
has been found by the writer in a good state of preservation after 
six weeks in this element. 
The color of the egg when first laid (PL III, fig. 1) is opaque white, 
which changes to yellowish brown as the development of the embryo 
proceeds. The interior of the newly laid egg appears to be an even 
mass of yolk substance. When the egg contains a half -developed 
embryo the yolk substance seems to be consolidated into a central 
mass, indented at both extremities and surrounded by layers of 
