68 MOSQUITOES 



senibling- this form in all of tlieir early stages aud in 

 their periods of developnieut. 



The female lays her eggs upon the surface of the water, 

 balancing herself upon some floating objs'ct during the 

 operation, and extruding them in an irregular, raft-shaped 

 mass, which is usually sha[)ed something like a pointed 

 ellipse somewhat convex below and concave above, all of 

 the eggs standing on end and closely applied, side by 

 side, in from six to thirteen longitudinal rows, with from 

 three or four to forty eggs in a row. The number of eggs 

 in each batch varies from 200 to 400. As seen from above, 

 the G^g mass is gray-brown, from below, silvery-Avhite, 

 the latter appearance being due to a tilni of air which 

 protects them from the water. It seems impossible to 

 wet these es::g masses. They may be pushed under the 

 water, but bob up apparently as dry as ever. As the 

 eggs are very small, being only 0.7 mm. long, aud 0.16 

 mm. in diameter at the base, the entire e^g mass is not a 

 large object, seldom, in fact, reaching a length of more 

 than a quarter of an inch. The mass separates rather 

 regularly and the eggs are not stuck together ver}' firmly. 

 After they have hatched, the mass will disintegrate in a 

 few days, even in perfectly still water. The individual 

 eggs are slender, broader and blunt at the bottom, and 

 somewhat pointed at the tip. The tip is always dark 

 grayish-brown in color, while the rest of the Qg^ is dirty 

 white. Sixteen or more hours after laying, the eggs 

 hatch, generally about noon on warm days, but some- 

 times they will remain unhatched for two days or even 

 longer, especially in cold weather. 



