hungerford: aquatic hemiptera. 209 



mass above the net. After prodding among this material and getting 

 stung by Naucorids until a retreat was necessary, we would take the 

 material to the bank and work it over, taking dozens on the way." 



The "sting" of this insect is indeed painful for a time, and it leaves a 

 stinging, itching, burning sensation for some time, as the writer has 

 found. 



DESCRIPTION OF STAGES. 



Pelocoris femoratax. 



The following is taken from Bueno, 1903. The writer has reared 

 P. carolinensis in part, but has never had the time to describe the ma- 

 terial: 



TAe Egg. 



Size. "Length, 1.4 mm.; width, .6 mm.; altitude, .7 mm. 



Shape. "From above, imperfectly oval; from the side somewhat flat- 

 tened above, with a gradual rise toward the middle. The cephalic end is 

 more rounded than the caudal, descending to the line of attachment 

 with a shorter curve. This curve is somewhat depressed at the ex- 

 tremity of the ovum, from which depression arises the micropylar boss. 

 The form changes during incubation and just previous to emergence 

 the ovum is larger and rounder than when first deposited." 



Color. "Translucent, pearly white when deposited, growing darker 

 as development progresses. The surface is minutely punctulated in 

 lines, punctures set close together, giving the appearance of meandering 

 striations. As the time for emergence approaches, the character of the 

 markings changes. The chorion is still punctulated, but at the same 

 time engraved in distinct hexagons, produced by the punctulations." 



First Instar. 



Size "Length, 2.5 mm.; width, 1.5 mm. 



"Immediately after emerging from the ovum, the nymph is trans- 

 parent, white and colorless, except that each abdominal segment has a 

 broad, dark, luteous band at the connexivum. Also, the eyes are red 

 and well-marked. The tarsal claws of the second and third pairs of 

 pedes are dark and noticeable. The single claws of the first pair are 

 colorless and transparent. The short rostrum is transparent pale 

 luteous, 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 examined, 

 however, it is seen to resemble closely the adult in shape, allowing for 

 the diff'erence 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 succeeds in 

 doing only by vigorous swimming. If it relaxes its efforts, it immedi- 

 ately sinks to the bottom. Pelocoris swims back down when in this 

 condition. 



"When still uncolored, the dorsal vessel can be plainly seen pulsating 

 and the oily globules of the unabsorbed yolk moving in the abdominal 

 cavity." 



Second Instar. 



Size. "Length, 3.25 mm.; width, .2 mm. 



"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- 



14 — Sci. Bui. — 1669 



