TR AC HEAL GILLS OF LARVAE 



471 



of the rice plant " in the very midst of the water." In a Brazilian 

 species of Paraponyx described as Catadysta pyropalis, by W. Miiller, 



FIG. 450. Anterior end of larva of P. stratiolata, showing the head and first two thoracic 

 spfirnents, with their gills : A, a tuft of gills, much enlarged. After I)e Geer. 



the tufts are reduced to simple unbranched filaments, and the case 

 is more complex than in the European species (Fig. 449). 



Of coleopterous larvae breathing by tracheal gills there are but few. 

 The larva of Gyrinus (Fig. 454) respires by 10 pairs of slender, hairy 

 abdominal gills similar to 

 those of Corydalus, and the 

 stigmata are entirely want- 

 ing. Somewhat similar are 

 the tracheal gills of Hydro- 

 charis caraboides. Hydro- 

 bins has shorter setose gills, 

 our American species having 

 seven pairs of short setose 

 gills. It has two spiracles 

 at the end of the body, 

 through which the air is 

 taken by thrusting the body 

 out of the water. The larvae 

 of two other aquatic cole- 

 opterous genera, Pelobius 



and Cnemidotus, also have 



FIG. 451. Larva (1) and pupa (2 n) of Pitrufinnyo) 

 enlarged : at, stigmata. After W. Muller. 



