ENTOMOLOGICAL CABINET. 



BAETIS BIOCULATA. Samouelle. Stephens. 

 Ephemera bioculata. Lime. 



f Hngs very fine, transparent and irredescent ; ner- 

 vures reddish yellow : antennce short and slender : 

 eyes moderate : body reddish yellow, terminated by 

 two yellow filiments longer than the body, with 

 brown dots. 



Expansion of the wings 8 lines. 



Inhabits the banks of ponds and running streams. 



The Ephemeridce derive their name, says Stewart. 

 in his Elements of Natural History, — " from the 

 shortness of their life after they become perfect, for 

 they have previously lived one, two, or three years 

 in the water as larvae and pupae. Some species live 

 only a day, and others, as it is said, only a few 

 hours. The larvae have six feet, and six plumated 

 fins on the sides of the abdomen, by which they 

 swim : tbe pupa differs little, except in having at 

 the thorax the cases which inclose the future wings. 

 When about to undergo the last change, which hap- 

 pens generally about the end of May or beginning 

 of June, the pupa approaches the land, and settles 

 on a dry place ; the skin bursts at the head and 

 thorax, and the fly immediately appears with its 

 wings extended, and takes flight. But what dis- 

 tinguishes the Ephemera from all other insects is, 

 that it has still another skin to get rid of. For this 

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