2 6 



POPULAR SCIENCE MONTHLY 



Fig. 2. — The insect first emitting a clear fluid which fills 

 up the interspaces between its body and the stem of 

 grass upon which it rests. 



this action accompanies a discharge of fluid or is an attempt at 

 reaching for air I have not ascertained. Suddenly the insect begins 

 to make bubbles by turning its tail out of the fluid, opening the 



posterior segment, which 

 appears like claspers,and 

 grasping a moiety of air, 

 then turning the tail 

 down into the fluid and 

 instantly allowing the in- 

 closed air to escape (Fig. 

 3). These movements go 

 on at the rate of seventy 

 or eighty times a min- 

 ute. At the outset the 

 tail is moved alternately 

 to the right and left in 

 perfect rhythm, so that 

 the bubbles are distrib- 

 uted on both sides of 

 the body, and these are 

 crowded toward the head 

 till the entire fluid is 

 filled with bubbles, and 

 the froth thus made runs 

 over the back and around 

 the stem (Fig. 4). 



Even when partially 

 buried in these bubbles 

 the tail is oscillated 

 to the right and left, 

 though when completely 

 immersed the tail is only occasionally thrust out for air which is 

 allowed to escape in the mass apparently without the right-and- 

 left movement, though of this I am not sure. It is interesting to 

 observe that in half a minute some thirty or forty bubbles are 

 made in this way — a bulk of air two or three times exceeding the 

 bulk of the body — without the slightest diminution in the size of 

 the body. 



If the insect is allowed to become dry, by resting it upon a piece 

 of blotting paper, and is then placed upon a piece of glass and a 

 drop of clear saliva be allowed to fall upon it, it proceeds to fill up 

 this fluid with bubbles in precisely the same manner as it did 

 with its own watery secretion. It is quite difficult to divest the 

 creature of the bubbles of air which adhere to the spaces between 



Fig. 4.— Entire fhrd filled witli bubbles, and the froth 

 thus made enveloping the stem. 



Magnified Figures of Apiirophora, showing Succes- 

 sive Stages in the Production of Froth. 



