$58 ORDER IV. Phryganea, 



■ ' m ■ ■ 



Phryganeae, and given to the firft the generical 

 name of perla. Thefe perU differ from the 

 other Phryganeae (to which he has preferved 

 that generical name) not only in the appendices 

 of the tail, but alfo in the pofition of the wings, 

 which, in the latter, decline from the inner mar- 

 gins, towards the fides, fo as to refemble the 

 ridge of a houfe, and are curve, or turned up- 

 wards, at their extremity ; and in the number 

 of articulations, which compofe their tarfi, thefe* 

 in the Perla, are but three j in the Phryganea 

 they are five. 



The Perlas and Phryganese, however, do not 

 feem to differ generically - 9 their larva perfe&ly 

 tefembling one another, and their manner of liv- 

 ing the fame ; they likewife perform their metar- 

 morphofis in the fame feafon, and in the tubes 

 in which they dwell while larvse. The lattef, 

 however, remain confiderably longer in thechry- 

 falis than the Perla*. In the year 1768, I had 

 an opportunity of obferving the metamorphofis 

 of three of the perls, and four phryganea ; 

 the Chryfalids were all kept together, and 

 in the fame degree of heat : two of the perfeft 

 infedls were produced on the eighth, and ano- 

 ther on the ninth day (after their refpedtive 



transfor- 



