THE ANIMALS AND MAN 



Books of insect classification are Comstock's "Manual of 

 Insects" and Kellogg's "American Insects." 



Insects live both on land and in water, but the aquatic 

 kinds are almost wholly limited to fresh water. A few 

 species live on the surface of the ocean, however, and a few 

 others on the water-drenched rocks and seaweeds between 

 the tide-lines. 



Among the most interesting insects to study in the field 



and to keep alive 

 and observe in the 

 schoolroom are the 

 water-bugs and bee- 

 tles to be found in 

 almost any brook or 

 pond. Collect various 

 kinds alive and keep 

 in the schoolroom aq- 

 uarium (Appendix II). 

 Running swiftly 

 about on the surface 

 may be seen rather 

 large, blackish, nar- 

 row-bodied, long-leg- 

 ged insects known as 



FIG. 67. A water-strider, Hygrotrechus sp., water-Striders Or pond 

 adult. (Twice natural size.) skaters (fig. 67). 



When at rest they hold the front pair of legs, which 

 are short and stout, projecting forward close to the 

 head, ready to grasp and hold small insects, the blood of 

 which they suck by means of a sharp, strong, piercing beak. 

 Their feet make small dents or dimples in the surface film, 

 but do not break through. Do they ever dive or swim in 

 the water ? Can they leap ? Are they winged or wingless ? 

 The immature water-striders have the body much shorter 

 than that of the adult. To be found also at the surface of 



