186 
Chapter XVII 
Anophelinae—The Ovum 
The Ovum 
Anophelines in captivity generally lay their eggs 
on some floating object, but also upon the surface of 
the water. When laid on a solid object, and even 
when laid on the water, the eggs are deposited in a 
piled up mass. Later, the ova, if on water, often form 
very regular and beautiful patterns. Brick-red masses 
of eggs are sometimes laid. These do not develop 
further. 
Observe (i) the arrangement in equilateral triangles 
and star patterns (Fig. 24). 
(ii) The arrangement in rows of eggs lying side 
by side. 
Both patterns are dependent upon the shape of 
the individual ovum ; ova belonging to type 1 forming 
stars, and ova belonging to type 2, rows. 
The number of ova varies, but is usually about 
one hundred. The size of the ovum varies with 
different species from about o’6 to I’o mm. 
Duration of Egg Stage. —Temperature is no doubt 
an important factor. Thus the egg stage in A. 
maculipennis lasts from two to four days, whereas in 
Ce. argyrotarsis it is one and a half days in Havana. 
In M. rossi it is about forty-eight hours. 
Anopheline ova (with one or two exceptions as 
yet described) are boat shaped, with an approximately 
