ARTHROPODA 



179 



morphosis. The common ''fish moth " or stive}' fish attacks starched 

 clothing, book bindings and wall paper paste, and the " snow flea " 

 sometimes gets into maple sap. 



Order 2. Ephemerida. — The May-flies have delicate wings, 

 poorly developed mouth parts and an incomplete metamorphosis. 

 The young May-fly lives in the water. Adult May-flies are said to 

 take no food, but to mate, deposit their eggs and die, all within the 

 short span of twenty-four hours. (Figure 82.) 



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Fig. 82. Young nymph of May-fly, showing tracheal gills. (After Jenkins and 

 Kellogg, from Kellogg and Doane, Zoology and Entomology. Courtesy of Henry Holt 

 & Co.) 



Order 3. Odonata. — The dragon flies, as larvae and as adults, 

 are important enemies of mosquitoes. They have large compound 

 eyes, four membranous wings and strong, biting mouth parts. 



Order 4. Plecoptera. — The stone flies are less important as fish 

 food. The nymphs live in running water where they cling under 

 stones. 



Order 5. Isoptera. — The termites or " white ants " are found in 

 the tropics in great abundance, where they destroy houses and other 

 structures made of wood. Some species attack soft plants and living 

 trees. In Africa, they sometimes build pyramidal nests twenty feet 

 high. The termites are social insects. (See p. 484.) 



Order 6. Corrodentia. — The book-lice are wingless insects 

 frequently found defacing the paper and bindings of old books. 

 Bark lice are winged forms feeding on lichens, oak leaves and other 

 foliage. 



Order 7. Mallophaga. — There are about fifteen hundred species 

 of biting lice which live among the feathers of birds or the hair of 

 mammals. While they are not sucking forms, they cause bleeding 

 and the results are almost as bad. They irritate the animals which 

 resort to dust baths. 



