VIII 



MAY-FLIES 



301 



sheaths of the wings and tail-filaments are shed ; the 

 antennae, which were previously conspicuous, become 

 far more delicate, and also much shorter in the 

 winged Insect than in the larva. The eye, which 

 was flat and smooth in the larva, is changed into a 

 many-faceted, compound eye. The legs and tail- 



FIG. 91. Fresh-emerged fly of Palingenia longicauda, male. From S\vammerdam ; 



Biblia Natures. 



filaments become as long again as they were in the 

 larva, while the third or middle tail disappears 



altogether. 1 



1 In those Ephemeridas which, like Palingenia, lose the 

 middle filament at the last moult, it is observed that there are 

 only two filaments in the fresh-hatched larva. To these the 

 third is added. When the fly emerges, the third filament is no 



longer to be seen. 



