126 INSECT LIFE. 



with it carefully brush these hairs toward the side of 

 the body so as to uncover the furrow. When this is 

 done there can be seen on the sloping outer side of 

 the furrow a small hole in each of the segments of the 

 abdomen ; these are the spiracles or breathing holes. 

 Note that the ridge on the middle of the belly ends 

 behind in a sharp, projecting point ; and that on each 

 side the edge of the body bearing the fringe of hairs 

 also ends behind in a similar point, between which 

 and the tip of the abdomen there is quite a space. 

 This space serves as an opening to an air-chamber 

 between the wings and the abdomen. 



8. Take from the aquarium two or three living 

 specimens and put them into a tumbler which is 

 nearly filled with water. Be careful not to be stung 

 while doing this. 



9. While a specimen is resting quietly at the sur- 

 face of the water, study it with a lens. Make a draw- 

 ing showing the arrangement of the hairs on the 

 abdomen of the living specimen while in the water; 

 this arrangement is very different from that seen on 

 the pinned specimens already studied. 



10. Observe, on the living specimen in the water, 

 the hole near the tip of the body through which the 

 air passes into the chambers beneath the fringes of 

 hairs and into the air-chamber between the wings and 

 the abdomen. 



11. Study the pinned specimens again, and make 

 sure that you understand how the air can pass to 

 the chambers referred to in the preceding para- 

 graph. 



12. On the pinned specimens study the first ab- 

 dominal segment on the belly side, and observe the 



