MRS. COATES'S BATH. 73 



boatmen of all sizes may be seen floating with their 

 heads downwards, the swimming-legs spread wide by 

 way of balancers, and the tips of their bodies just pro- 

 truding from the surface. A hasty step, however, a 

 sudden movement, or a shadow, even of a passing bird, 

 thrown on the water, will alarm the insects, and they 

 will scurry off in all directions. 



By watching these insects very carefully in a bottle, 

 and keeping that bottle constantly before my eyes on 

 my desk, I have been enabled to observe the course 

 which the air takes in respiration, the partly trans- 

 lucent wing-cases enabling the bubbles to be traced as 

 they pass like globules of quicksilver under the wing- 

 cases and finally into the water. The air is taken in 

 at the end of the tail, and introduced into the space 

 between the wing-covers and the body. It is then 

 gradually drawn forward until it reaches the base of 

 the wing-covers, and is lastly forced out just where the 

 wing-covers fit against the breast. When the insect is 

 perfectly quiet the process may be seen going on with 

 perfect regularity, the air being taken in near the tail, 

 working its way under the wing-covers, and at last 

 squeezed out near the breast, when it ascends in bubbles 

 to the surface. In this position the water-boatmen are 

 accustomed to wash themselves. They are as cleanly 

 as cats, and perform the operation of washing in a 

 very similar manner, leaving not a limb nor a part of 

 the body untouched. Sometimes they will rest on the 

 surface of the water, but this time with their backs up- 



