320 NATURAL HISTORY OF AQUATIC INSECTS CH. 



for walking, but owing probably to their unusual 

 length, the gait of the male Insect is slow and 

 awkward. At the extremity of the fore leg are two 

 flattened appendages, diverging from one another, 

 and armed with minute spines, as if to improve the 

 holding-power of the legs. 1 In the female the fore 

 legs, though not so long, are raised, as in the male, 

 The male has also claspers at the end of the abdomen, 

 much larger compound eyes than those of the 

 female (as in many other Insects) and longer tail- 

 filaments. 



" The eggs are discharged all at once, in the form 

 of a yellowish-white, oblong disc, which is dropped 

 into the water, probably as the female flits over the 

 surface. It sinks at once, and the eggs separate from 

 one another. 2 



" The flies emerge at the end of May or the begin- 

 ning of June, always towards sunset. Some hundreds 

 may be seen together, dancing in the air, usually 

 around some tall tree. The males greatly exceed 

 the females in number. They rise by the action of 

 the wings, and when they have ascended five or six 

 feet above the tree, allow themselves to sink slowly 

 the wings being outspread and motionless, and the 

 long tail-filaments raised and widely separated. Late 



1 In some species the fore leg of the winged male has a sort 

 of kink or angle, which may be used to hold the female (Baetis, 

 Chloeon). 



2 The process of egg-laying seems to exhibit great variety in 

 the different species of Ephemeridae. Females of Baetis flu- 

 minum, Chloeon dipterum, and Chloeon Rhodani have been 

 found among stones under water, as if they had descended to 

 lay their eggs there. 



