Vol. XXviii] ENTOMOLOGICAL NEWS. 273 



days, for the fifth instar 12 days. Eggs laid July 12th hatched 

 July 17th, averaged 6 days for each of the first four instars 

 and 1 1 days for the fifth — a total of 40 days from the deposi- 

 tion of the egg to the adult stage, a period somewhat shorter 

 than for the spring generation. 



Description of Developmental Stages. 



The egg. A description of the egg of this species was given 

 by Bueno (1905) as 1.9-2 mm. in length, clear glistening pearly 

 white when recently deposited. Chorion sculptured in irregu- 

 lar hexagons. Shape elongate oval. A large series of freshly 

 laid eggs averaged 1.75 mm. in length, varying from 1.625 mm. 

 to 1.813 mm. The diameter ranged from .5 mm. to .6 mm. 

 The shape of the egg is modified as the embryo develops. The 

 embr}'o lies with its back to the attached side of the egg as a 

 rule. After a few days incubation the eye spots begin to ap- 

 pear as faint pink blotches — darkening as development takes 

 place till shortly before hatching the black hairs bordering the 

 various portions of the body of the nymphs are visible through 

 the chorion. 



Hatching takes place upon bursting the cephalic end of the 

 egg as shown in the photograph. The nymph comes forth 

 swathed in a clear membrane, gradually working its way, by 

 backward and forward movements, till it is nearly clear of the 

 egg shell, whereupon the embryonic sheath splits and slowly 

 the new bug frees itself, the swimming legs being the last to 

 leave the shell. As the legs are freed they spring out into 

 position. When at last the little bug is clear, it rests as though 

 exhausted, then it makes, during the next fifteen or twenty 

 minutes, intermittent endeavors to attain the surface. In 

 these efforts it approaches the surface head uppermost and is 

 heavier than the water — dropping to the bottom as soon as its 

 struggles cease. Finally it may succeed in hooking a front 

 claw into the surface film where it will hang suspended for 

 some minutes. Finally it turns on its side, pierces the sur- 

 face film, then darts below, the guard hairs closed over a bub- 

 ble of air — up to this time the guard hairs of the abdomen 

 have rested limp against the body. 



