28 POPULAR SCIENCE MONTHLY. 



will crawl about the table or even on the dusty floor and live for 

 an hour or two in this condition. The usually glabrous surface 

 of the body, however, becomes shriveled after a while. On the 

 other hand, it immediately sinks in water, and will live for some 

 time immersed in this way, and this leads me to believe that the 

 appendages above described may perform a slight respiratory func- 

 tion. The fact that the insect immediately sinks may be cited as 

 an additional evidence that it does not emit air. 



It is interesting to observe that regarding this stage of Aphro- 

 pliora as an aquatic stage, since it lives immersed in fluid, we have 

 the same behavior that we observe in the aquatic stages of other 

 Hemiptera, as well as in insects of other orders. The great water 

 beetle Hydrophilus has an aquatic larva. Myall, quoting Lyonet, 

 says: "They never remain long at the bottom of the water; air is 

 necessary for them, and this they take in by the tail, which they 

 raise from time to time to the surface of the water." In the larva 

 of Dysticus, another water beetle, the only functional spiracles are 

 the last pair, opening at the tail. The little oval beetles, known 

 as whirligigs, from their rapid whirling motion, when swimming 

 on the surface of the water carry down a bubble of air on the end 

 of the abdomen, and when this has been exhausted in the process 

 of respiration rise to the surface for a fresh bubble. The larvae 

 of some forms are furnished on each side with long respiratory 

 filaments. 



A number of neuropterous insects whose early stages are passed 

 in the water are furnished with branchial tracheae or false gills. 

 These consist of filaments springing from the sides of the abdominal 

 segments. In the early stages of certain dragon flies the rectum 

 supports epithelial folds which are filled with fine tubes from the 

 tracheal system. Among certain aquatic insects belonging to the 

 order of Hemiptera the creatures reach out the hinder portion of the 

 body to secure air. Dr. Myall, in his very interesting book on the 

 Natural History of Aquatic Insects, says : " A Nepa or a Ranatra 

 may sometimes be seen to creep backward along a submerged weed 

 until the tip of its breathing tube breaks the surface of the water." 



The Apliropliora while immersed in the watery fluid, whether 

 secreted by itself or consisting of clear water which has been sup- 

 plied to it, reaches out for air in a precisely similar manner. Pri- 

 marily the froth made by this insect not only keeps the body moist, 

 but acts as a protection against its enemies. 



A number of individuals may often be found in one fleck of 

 froth, and they are entirely hidden from sight while immersed 

 in this way. The viscid character of the fluid secreted insures 

 the retention of the air the insect collects in the form of little 



