36 



closely together at the sides by some gummy secretion, and arranged 

 in rows. The mass with Anopheles, however, is laid loosely npon the 

 surface of the water, each egg lying upon its side instead of being 

 placed upon its end as in the egg mass of Culex. They are not attached 

 together except that they naturally float close to each other and there 

 are from 40 to 100 eggs in each lot. In Ctdex 2ninge7is the individual 

 egg is 0.7 mm. long and 0.16 mm. in diameter at the base. It is 

 slender, broader, and blunt at the bottom, slenderer and more pointed 

 at the tip. The tip is always dark grayish brown in color, while the 

 rest is dirty white. The egg of Anopheles when seen from above is 

 of a rather regular elliptical outline, the two ends having practically 

 the same shape; seen from the side, it is strongly convex below and 

 nearly plane above; seen from below, it is dark in color and when 

 examined with a high power is seen to be covered with a reticulate 

 hexagonal sculpturing. At the sides, in the middle, there appears a 

 clasping membrane with many strong transverse wrinkles. Seen from 

 above, the egg is black except for a clasmng membrane which nearly 



Fii;. 1-.—Ano])h(li.< qiiKdrimaadatus: Newly hatched larva— greatly erilarg-ed (original). 



meets on the middlt^ line in the middle third of the body, but retires to 

 the extreme sides for the anterior and posterior thirds. At each end 

 the color is lighter, with a group of from 5 to 7 minute dark circular 

 spots. It is 0.57 ram. long. Eggs laid April 26 hatched April 30. 

 Others laid May Id and l-i hatched May 16 and 17. 



The larva. — The larva is quite as unlike that of Oulex pimgens as 

 is the egg. It differs in structure, in its food habits, and in its cus- 

 tomary position so markedly that it can at once be distinguished with 

 the utmost ease. The larva of Culex, it will be remembered, comes 

 to the surface of the water to breathe, thrusting its breathing tube 

 through the surface layer and holding its body at an angle of about 

 4.5 degrees with the surface of the water. While in this position its 

 mouth parts are in motion and it is taking into its alimentary canal 

 such minute particles as may be in the water at that depth, but these 

 are naturally few in number and the larva descends at frequent inter- 

 vals toward the bottom to feed. The want of oxygen, however, causes 

 it to wriggle up again to the surface at very frequent intervals. Its 



