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NATURE STUDY REVIEW [8:5— May, 191:J 



Adult Insects. 



8 



-6, Water Strider; 7, Marsh Treader; 8, 

 Whirligig Beetle. 



antennae, and a curious, long, cylindrical head on the sides of 

 which, and well back from the front end, are the eyes, while on 

 the lower side is the deadly beak. They feed upon insects that 

 fall into the water. The writer has collected them by making 

 long sweeps with the net among the water plants just at the sur- 

 face of the water or by dragging the open mouth of the net swift- 

 ly over the surface of the mud near the water's edge. In the 

 aquarium, fed them on flies and mosquitoes. 



The Whirligig Beetles (Fig. 8.) 



At almost any time from March to October these oval, black- 

 ish, surface beetles can be seen on almost every pond or sheltered 

 nook of quiet streams. They always occur in groups which may 

 be small or large. Sometimes the group will number about ten, 

 while again the writer has seen groups which must have num- 

 bered several thousands. The young collector will find a very 

 interesting occupation in watching the behavior of one of these 

 groups in its native haunt. A field or opera glass will be of some 

 aid in this kind of study. The eyes of these active little fellows 

 are curious in that each eye is divided into two parts so that there 

 are really two eyes on the upper side of the head which look into 

 the air, and two on the lower side which look into the water. 

 The front legs are much longer than the others and are used for 

 grasping the food. So active are these insects that they are rather 

 hard to collect. Quietly approach one of these groups, very 



