26 BROAD-SHOULDERED WATER-STRIDERS. 
a thick, blunt cone. The antennz are four-jointed, either short 
and quite stout, or long and slender. 
The insects are always found near the shores of water, and 
run over the surface in search of their food. They are well pro- 
tected against getting wet by a beautiful pubescence, which rubs 
off rather easily. 
All the insects belonging to this family are small, even 
minute, but few measuring more than one-third of an inch in 
Fic. 19b.—Rheumatobates rileyi Berg. Female imago, with the hind tarsus en- 
larged; a,tarsus of foreleg; b, anal segment from below still more enlarged 
(Heidemann, del}. After Insect Life, Div. of Entomology, Dep. of Agriculture. 
length. If inspected with a magnifying lens they are most 
beautiful objects. Some never become winged; others have am- 
ple organs of flight. According to Uhler they walk over the 
water with the greatest facility, and often use the longer middle 
legs like oars, with somewhat of a rowing motion. It is interest- 
ing to observe them on the quiet surface of the creeks, where 
they love to remain together in groups, staying together motion- 
less for hours at a time, and then, when startled by the ap- 
