104 Journal New York Entomological Society, t^'o'- ^i^- 



stronger than itself, the struggles of the dragon-fly nymphs usually 

 ceasing within a short time after the piercing organs of a Ncpa have 

 been pushed into their bodies. That this is the effect of a fluid 

 which Ncpa injects into them was only too well demonstrated on 

 ourselves. While one of us was carelessly holding several Nepas in a 

 closed hand, one of the insects suddenly punctured the palm, caus- 

 ing an intense pain and soon afterward a considerable swelling. 

 Locy (32, pp. 355-6) has found in the genera Lethocerus, Belostoma 

 and Ranatra what he calls the " cephalic glands," which may be the 

 source of a poisonous secretion. " When these insects are irritated, a 

 secretion is freely thrown out around the base of the beak, which 

 produces death very quickly when introduced on a needle point into 

 the body of an insect." 



Respiration. — Belostoma will often leave its resting place in the 

 water and swim to the surface to obtain a fresh supply of air. Dur- 

 ing this respiratory act, one may notice a pair of strap-like append- 

 ages protruding above the surface-film from the posterior end of the 

 abdomen ; within a short time these are retracted and usually with- 

 drawn from sight. If the wings of this aquatic bug are raised while 

 the insect is below the surface of the water, a silvery coating -of 

 air will be noticed on the dorsal side of the abdomen. Unquestionably 

 Belostoma carries a reserve supply of air between the wings and the 

 abdomen. If a specimen emersed in water is examined under a 

 binocular microscope, one can readily see that the pubescence de- 

 scribed by Bueno (10, p. 192) on the under surface of the body holds 

 a thin film of air, which probabh- supplies the abdominal and thoracic 

 spiracles. 



Uhler {2^, p. 255) in writing of the family Belostomatidse says: 

 " A remarable feature of all the genera is in the presence of a pair 

 of flattened, narrow, strap-like appendages at the end of the body 

 which are extensible, but not concerned with respiration . . . . " Bueno 

 (10, p. 192), however, found near the base and below the outer edge 

 of each strap-like appendage in Belostoma flumineum, " a deep sunk 

 orifice in which lies the great spiracle from w^hich springs the large 

 tracheal trunk of the main system." 



When Belostomas are disturbed while taking in a new supply of 

 air, some specimens will spurt forth, on rare occasions, a stream of 



