146 LEAVES FROM MY NOTE-BOOK. 



palings, not far from water. When the larv^ hatch out, they 

 travel to the water, and Mr. Miall says he has often seen the fresh 

 hatched larvae wriggling out on leaves many yards from the nearest 

 stream or pond. " How they find the way," he adds, " I do not 

 know," and that indeed is just the puzzle ! 



It would be impossible to condense, with any justice, the 

 extraordinarily interesting accounts of the life-histories of Ephe- 

 meridce, taken from the works of Swammerdam, Reaumur, De Geer, 

 Sir John Lubbock, and other naturalists ; but a few points of 

 interest may be alluded to. The Ephemeridce have, in their life- 

 history, characteristics equally interesting and puzzling. Their 

 lives as larvae are comparatively long, and, in their aquatic stage, 

 the creatures are provided with most beautiful and complicated 

 feathery or leaf-like gills ; they have no conspicuous pupal stage,''' 

 but undergo numerous moults, amounting in Chlocon to as many 

 as twenty-one ; they burst suddenly into aerial life, their wings 

 expanding with such suddenness as to baffle the sight ; the flat 

 smooth eyes of the larval stage are succeeded by many-faceted, 

 compound eyes, and two long tail filaments enable them to rise 

 for their giddy flight over the water. All these complicated, 

 exquisite arrangements lead up to a life of but a few hours — 

 sometimes of only half-an-hour's duration ; some species emerge 

 at sunset, others after sundown ; but all alike are destined to a 

 rapid death, as in their perfect state they can take no food. 



Reaumur fully describes his researches as to the emergence of 

 Poly??iitarcys, the species of Ephemeron most common in the neigh- 

 bourhood of Paris. He says : " In 1738, I resolved to attend to 

 the emergence of this fly, and engaged an angler of Charenton to 

 tell me when the first signs appeared, which were expected between 

 St. Laurence's Day and Notre Dame d'Aout, that is between the 

 loth and 15th of August. This year the flies appeared on the 

 1 8th. On the 19th I received warning from my angler, and the 

 same day, three hours before sunset, I took his boat to examine 

 the banks of the Marne and Seine. Where the shore was level 

 and sheltered from the wind, heaps of dead Ephemerce could be 

 seen. During this excursion by water I removed some clods of 



* See note, Natural History of Aquatic Insects, p. 305. 



