HUNGERFORD: AQUATIC HEMIPTERA. 105 
First Instar. 
Size. See the table presented below. 
Color. When first hatched it is white, with red eyes darkening to 
amber and green as it ages. To the unaided eye it is greenish brown. 
Thus it is much darker than the older nymphs, quite distinct in coloring. 
The tips of the appendages are dark, while the limbs themselves are pale. 
Structural Peculiarities. The general form is stouter and more robust 
than that of the later stages. The body and limbs are clothed with 
hairs and bristles. The head and thorax bear a few stout bristles 
and the antenne bear on the first segment several (usually three 
or four) stout bristles directed mesally and the terminal segment 
is thickly covered with fine hairs. The limbs, besides bearing many 
hairs, possess a number of black bristles arranged as follows: One 
stout bristle is prominent near the distal end on the anterior margin 
of the meso- and metathoracic femora. The metathoracic tibie are 
beset with numerous irregularly arranged bristles, terminating with 
one larger than the others. 
The antenne are stout and as long as the body, four-segmented, the 
terminal segment is somewhat broadened and as long as the other three. 
The head bears no indication of ocelli, but does possess the black bristles 
indicated in the later instars. 
The limbs are stout, the tarsi one-segmented and end in two claws. 
The abdomen bears a dorsal pore on the median line of the dorsum of 
the fourth abdominal segment. 
Later Instars. 
The second and later instars are bright green in color and more slen- 
der in form. They possess relatively fewer hairs on the body, but retain 
the black bristles in the positions indicated in the first instar. There 
appear in these later instars one black bristle on anterior margin of 
fore femur and two on the other femora. The structural characters re- 
main constant until the adult stage is reached, when the following 
changes become apparent: 
The first antennal segment possesses but one black bristle instead of a 
number of them (usually). 
The limbs are more slender and tarsi three-segmented. 
The connexivum is broad and the sexual characteristics appear. 
In the winged female there appear two dark ocelli-like spots on the 
vertex. 
The winged forms are often found with membrane missing. They 
have been observed to break away this portion of the wing with the hind 
tibia, exposing the tip of the abdomen. 
