ZOOLOGY. 213 



a few hours, and in others, less than one hour, during which 

 time they propagate their species, and die. 



They are all aquatic insects, in thp imperfect state, like the 

 preceding, living entirely in the water ; the larvae is six 

 footed, active, is tailed, and is greedily devoured by trout, 

 and other fish ; possesses lateral processes, or fins ; the pupa 

 resembles the larva, except possessing the rudiments of the 

 future wings. 



3. Phrifganea. Month without teeth ; feelers four ; stem- 



mata three ; antenna: setaceous, longer than the tho- 

 rax ; wings equal, incumbent, the lower pair plaited. 



The individuals of this genus bear a considerable resem- 

 blance in their adult state, to some of the Phalenae, but are 

 distinguishable by their not possessing the spiral tongue : the 

 larv« is six-footed, and resides at the bottom of shallow 

 waters, in a case, composed of small pieces of Straws, which" 

 are glued together by an exudation from the insect, the case 

 is tubular ; lined with silk-like filaments, and is open at 

 each end ; they feed on aquatic insects, the spawn of fishes, 

 as also on the young fry. 



4. HemeroMus. Mouth furnished with two teeth ; palpi 



four ; stemmata wanting ; thorax convex ; antennas 

 longer than the thorax, in some species setaceous ; in 

 others, pectinated on one side; fig. 31, plate 3; mngs 

 deflected, smooth, not plaited. 



The eggs of these iniects are of a highly curious structure^ 

 V 3 



