552 Animal Biology 



Fig. 275. — An adult Mayfly or lakefly of the order Ephemerida. Observe dif- 

 ferences in fore- and hind-wings, and the long slender, many-jointed "tails" at the 

 tip of the abdomen. The adult takes no food and lives a very short time, while 

 the larva (naiad) with its abdominal tracheal gills develops in the water from one 

 to three years (depending on the species). 



ODONATA 



EPHEMERIDA 



TR/CHOPTERA 



PLECOPTERA 



Fig. 276. — Representative insects of the orders Odonata, Ephemerida, Trichop- 

 tera, and Plecoptera. Immature stages in the water: adults above. (From 

 Krecker: General Zoology, published by Henry Holt and Company, after Pearse.) 



