POND LIFE. 



139 



1. Note that the head overlaps the prothorax in- 

 stead of being inserted in it, as is usually the case 

 with insects. 



2. Observe the very large, three-cornered eyes. 

 The antennas are very small, and are concealed under 

 the backward-projecting edge of the side of the head. 



3. Observe the lower part of the front of the 

 head ; it tapers to a blunt point, but it is not pro- 

 longed into a slender beak, as is usual with bugs ; 

 near the tip of the head there is a small opening, 

 through which the sucking mouth-parts are pushed 

 when in use. 



4. The prothorax is conspicuous above, and is 

 marked by transverse stripes ; on the sides it is very 

 short, and below it is almost completely covered by 

 the head ; this brings the fore legs very near to the 

 mouth. 



5. Make a drawing of one of the fore legs : note 

 that the tarsus consists of a single segment, is scoop- 

 like in form, and bears a comblike fringe of bristles. 



6. Make a drawing of a middle leg, and note the 

 very long, slender tarsal claws. What is the use of 

 these claws? 



7. Make a drawing of a hind leg. What are these 

 legs fitted for? 



8. Study the lower side of the abdomen of sev- 

 eral specimens. In the females the segments are of 

 the usual form, but in the males some of them, and 

 especially the last four, are very unsymmetrical, 

 being, upon one side, broken into irregular-shaped 

 fragments. The cause of this is not known. 



9. Indicate by labels the sexes of your pinned 

 specimens. 



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