170 Journal New York Entomological Society. [v<.i. xi. 



ous, darker at the tip. A seta issues from the posterior angle of each 

 abdominal segment, at the connexivum, on the dorsal surface. About 

 eight hours after emergence the insect is much darker in color. 



In shape the young Pelocoris resembles nothing so much as the 

 suctorial midnight prowler, at a superficial glance. Carefully ex- 

 amined, however, it is seen to resemble closely the adult in shape, allow- 

 ing for the difference in size and absence of wings. 



When recently hatched its abdominal air coating is absent, and 

 the young insect finds it difficult to reach the surface, which it suc- 

 ceeds in doing only by vigorous swimming. If it relaxes its efforts, it 

 immediately sinks to the bottom. Pelocoris swims back down when 

 in this condition. 



When still uncolored, the dorsal vessel can be plainly seen pulsat- 

 ing and the oily globules of the unabsorbed yolk moving in the ab- 

 dominal cavity. Size: Longitude, 2.5 mm.; latitude, 1.5 mm. 



Out of a large number of individuals obtained from ova, only five 

 reached the second instar, one in ten days after emergence, three in 

 eight days and one in seven. This would give an average period of 

 eight days for the first instar. 



Second Nymphal Instar. 



The appearance after the molt is practically the same as after emer- 

 gence from the ovum, except that there is a dark, somewhat triangular 

 shaped blotch extending from the caudad margin of the thorax to the 

 fourth abdominal segment, apparently produced by the abdominal con- 

 tents. The pulsations of the dorsal vessel can also be seen in this in- 

 star under the same conditions as before, save that the yolk is, of 

 course, totally gone. Size: Longitude, 3.25 mm.; latitude, 2 mm. 



Three alone survived till the second moult, two making the ecdysis 

 in nine days and one in six. It may safely be assumed that the longer 

 period is nearer the average, since the more rapid molt occurred in 

 very hot weather. 



Third Nymphal Instar. 



The preceding description applies to this etjually well. Size : Lon- 

 gitude, 4.8 mm.; latitude, 3 mm. 



The succeeding observations have been made on the two survivors, 

 which I safely carried through to maturity. However, 1 did not ex- 

 amine these at all closely for fear of losing them, so my notes on the 



