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Chapter XV 11 1 



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. 19). 



(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 i 

 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. macultpennis 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 exception as yet des- 

 cribed) are boat shaped, with an approximately 



