114 Journal New York Entomological Society. [Vol. xxv. 



Cottonwood leaves placed in the aquarium for the purpose. The leaf 

 bits were then transferred to petrie dishes where a careful study of 

 them with the binocular was possible each day. The eggs are laid 

 on the dead leaves and stems of plants lodged in the water. We have 

 found as many as seventy-four eggs on one Cottonwood leaf. 



There are several generations a year and the eggs of the sum- 

 mer generation are often found on floating weeds and any other 

 available support in the water. The writer has found the eggs of 

 this species, of a small undetermined species, and even those of 

 Rhamphocorixa acuminata, which has a peculiar tendency to attach 

 its eggs to the carapace and abdominal pleurites of crayfish, covering 

 tin cans lodged in the water, boards, floating and attached, and even 

 to the shells of living snails. Sticks of log wood of various sizes are 

 sometimes so covered with the eggs of this corixid of the summer 

 generation that it is impossible to handle them without destroying 

 hundreds of eggs. 



The Ovum. 



Shape. — The shape of the tgg of this species resembles a wooden 

 top, such as the American boy keeps. It sits upon the button end in 

 a disc of leathery material. Eggs of a somewhat similar shape are 

 figured by Metschnikoff, and have been described as pyriform. 



Color. — The color, when first laid, is pearly white. This gradually 

 changes to a deep yellow. The red eye spots show very plainly in the 

 more advanced stages. These spots begin to appear about the fourth 

 day as rather indefinite pink patches which gradually darken to a 

 deep red, by which time they then have assumed definite and char- 

 acteristic shape. 



Size. — The greatest length is .581 mm. The greatest diameter is 

 .520 mm. 



The tgg of this species is figured in Plate IX. 



The eggs of two other species are drawn to show the difference in 

 shape, and relative size. 



First Instar. 



^/_^^_-__General measurements : 



Mm. 



Width of head 50 



Greatest abdominal width 58 



Length of body i . 1 7 



Specific measurements : 



