HEMIPTERA. 135 



est across the prothorax. These Broad-shouldered Water- 

 striders constitute the family Veliidce. They pass the greater 

 part of their lives upon the surface of the water, often con- 

 gregating in schools containing hundreds of individuals ; but 

 they usually remain near the banks of the stream or pond, 

 and sometimes they leave the water, mov- 

 ing on the land with great freedom. Like 

 the members of the allied families, they are 

 predaceous. Figure 156 represents one of 



these insects somewhat enlarged. 



FIG. 156. Rhagovelia 

 co Ha ris. 



Family HYDROBATID^E (Hyd-ro-bat'i-dae). 

 The Water-striders. 



On the quiet pools of a running stream or the calm 

 waters of a protected pond may be found swarms of slender 

 long-legged insects that seem to find the water surface a 

 pavement well suited for their airy feet. If your approach 

 is stealthy you may see them resting motionless as if ab- 

 sorbed in gazing at their own reflections in the mirror below 

 them ; but disturb them, and so swiftly do they move 

 that they seem but darting lines as they circle around and 

 around each other in a mystic dance. If you watch them 

 closely you may see one leap into the air after some approach- 

 ing insect. 



These are the true Water-striders. In some of them the 



body is long and narrow, as 

 shown in Figure 157; in 

 others it is oval ; but in all 

 it is widest back of the pro- 

 thorax, thus differing from 

 the form seen in the pre- 

 ceding family. 



In the winter they stow 



FIG. 157. Hygrotrechus confonnis, tl 1 i 1.1 



themselves away under the 

 banks or at the bottom of the water, and do not come to 



