120 THE UNIVERSITY SCIENCE BULLETIN. 
First Instar. 
Size. Length of body, .676 mm.; width, .364 mm.; width of head, 
.3398 mm.; length of middle limb, 1.48 mm.; hind limb, 1.04 mm. 
Shape. Remarkably like that of Gerris. Head, thorax and abdomen 
closely joined. The indentation between the prothorax and mesothorax 
being more marked than that between the head and prothorax. The _ 
sides of the body parallel and the abdomen extremely short. Tip scarcely 
reaching distal end of posterior coxe. 
Color. Yellowish brown, a light Y-shaped line is present upon the ~ 
head, the stem of which passes posteriorly across the prothorax and 
widens to a broader band covering the median line of the long meso- 
thorax which is met posteriorly by converging lateral bands of the same 
color. Eyes dark red, some pink spots show in the Ist, 2nd, and base 
of the 4th segments of antenne. These are now almost obscured, but 
doubtless gave the pink color spots to the embryo within the egg shell. 
Limbs are smoky testaceous, but fairly light, as on the venter of the 
bug. The tip of the beak and the suture lines in front of the mesocoxe 
being dark. 
a eS ee oe eT S 
Genus RHEUMATOBATES Berer. 
Rheumatobates riley. 
Habitat. There are three species of this peculiar group of little 
bugs. They live on quiet waters. In Kansas R. rileyi is common enough 
on the muddiest ponds and pools. The male of this species is of most 
bizarre shape. (See plate XVI.) Note the clasping antenne and the 
strange twist to the hind femora. 
OO ee ee ee me eee 
Oviposition. Three summers have failed to disclose the nature of the 
oviposition. The ovipositor suggests that the eggs are hidden in the 
tissue of a plant. The writer figures this on plate XVI. 
Food Habits. They feed upon insects dropped upon the water, and 
if watched in a pool teeming with ostracods they can be seen to scoop 
them out of the water and carry them about on the upturned tip of the 
beak. 
Behavior. These insects are gregarious and very easily disturbed. 
DESCRIPTION OF STAGES. 
The Ovum. 
Size. Length, .728 mm.; width, .208 mm. 
Shape. Elongate cylindrical; one end bluntly pointed; the other 
end rounded and bearing a short projecting micropyle. 
Genus HALOBATES Eschs. zy 
Two species, H. micans, off the coast of Florida and H. sericeus off 
the coast of California. Little is known about these insects. Eggs 
found on a floating feather by the Vitor Pisani expedition appeared from 
the embryo within to be eggs of Halobates. Other females taken have 
been figured with eggs extruded and clinging to the abdomen. Their 
food must be the minute Crustacea of the water, for they range far 
from land and are taken on coast only when driven there by storms. | 
