REV. A. E. EATON ON RECENT EP1IEMERID.E OR MAYFLIES. 11 



stream like a heap of foam, whose resting-place (in New Guinea, at least) is generally 

 found in the mouth of a big fish. [See below, under Palingcnia ixipuana.'] 



OVIPOSITION AND THE EgG. 



Oviposition is usually performed in fresh water; a Cingalese Palmffenia, howeyer, 

 inhabits an estuary where the water occasionally must be brackish. Some short-lived 

 species discharge the contents of their ovaries completely en masse, and the pair of fusi- 

 form or subcylindrical egg-clusters laid upon the water rapidly disintegrate, so as to let 

 the eggs sink broad-cast upon the river-bed. The less perishable species extrude their 

 eggs gradually, part at a time, and deposit them in one or other of the following manners : — 

 either the mother alights upon the water at intervals to wash off the eggs that have issued 

 from the mouths of the oviducts during her flight; or else (Eaton, Trans. Ent. Soc, 

 London, 1873, p. 401) she creeps down into the water — enclosed within a film of air, with 

 her wings collapsed so as to overlie the abdomen in tlie form of an acute narrowly linear 

 bundle, and with her setfe closed together — to lay her eggs upon the underside of stones, 

 disposing them in rounded patches, in a single layer evenly spread, and in mutual con- 

 tiguity. This has been witnessed by me several times, and in the case of several species 

 of Baetis. The female on the completion of her labour usually floats up to the surface 

 of the water, ineffectively swimming with her legs, and, on emerging, her wings all at 

 once are suddenly unfolded and erected ; she then either flies away, or (as often happens) 

 if her seta? have chanced to liecome wet and cannot ])e extricated from tlic water, she is 

 detained by them until she is drowned. In some instances, however, the female dies 

 under water beside her eggs. 



The eggs, indefinitely numerous, are diversiform according to the genus, some being 

 subrotund, others elliptical. An appendage of various relative size is in certain cases 

 present at one end of the c^g ; for example, in Ccenis it is narrowly crescentic, but 

 in FyphemereUa it nearly equals the yolk itself in size, and forms in combination with it a 

 somewhat figure-of-8-shaped mass. 



The dixration of the egg-stage varies with the temperature to which the eggs are 

 exposed. Some of Folijmitarcijs virgo, kept in Dr. N. Joly's laboratory at Toulouse, were 

 hatched about six or seven months after they were laid. 



Professor L. Calori (1848) and Dr. E. Joly (1877) have recorded instances of larvi- 

 parition observed by them in Cloeon diptermn. Although they supposed that the young 

 were produced from impregnated eggs retained within the mother, perhaps for some 

 weeks, it may be conjectured, with equal if not greater probability, that these were the 

 produce of unfertilized ova advanced to maturity within the nymph and hatched as soon 

 as she became an imago. 



In the absence of elaborate contrivances, many Ephemeridse can be bred in captivity 

 if confined in flower-pot saucers, or other wide vessels, containing very little water, duly 

 protected from extremes of temperature. If the bottom be glazed inside, it should be 

 thoroughly strewn over with sand or fine river-gravel, that the insects need not die of 

 fatigue in struggling to maintain their footing upon it. Banunculus should not be 



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