438 



EPHEMERA. 



belonging to the natural order Contferee. Two o 

 them are hardy European dwarf bushes, the other is 

 a climber from Barbary. They are propagated by 

 layers or suckers. 



EPHEMERA (Linnceus.) A genus of neuro- 

 pterous insects, belonging to the section Subulicornes 

 of Latreille, and forming the type of the family 

 Ephemeridce, distinguished by the entirely mem- 

 braneous and almost obliterated structure of the 

 mouth, the parts of which are very indistinct, the 

 five jointed tarsi, the small size of the lower wings 

 which are even sometimes entirely wanting, and the 

 slender threadlike appendages with which the tail is 

 terminated. 



The name of this genus has been given in con- 

 eequence of the very short duration of the life of the 

 insect when arrived at the perfect state, it is derived 

 from the Greek, and signifies living only through a 

 day. The insects are the may-flies of anglers, whose 

 beautiful motions in the blaze of the evening sun, 

 alternately rising and falling, cannot have failed to 

 have attracted the notice of every observer of nature. 

 The body is soft, long, and slender. The antennae 

 are very short and three jointed, the wings are 

 generally carried either perpendicularly, or slightly 

 inclined. The legs are long and slender, without 

 bristles, the anterior pair being the longest, inserted 

 close to the head, and stretched out in front of the 

 body. The perfect insects generally appear in 

 ewarms about sunset, in fine summer or autumn even- 

 ing?, along the margins of streams, lakes, &c., and 

 occasionally in such numbers, that the ground is 

 shortly afterwards so completely covered with their 

 dead bodies, that in certain dietricts they are collected 

 in cart loads, and used as manure. One species, 

 Ephemera albipennis, is remarkable for the white- 

 ness of its wings, so that its swarms have all the ap- 

 pearance of a fall of snow. It appears to have been 

 this species, the proceedings of which are detailed by 

 Mr. A. H. Davis, in the Entomological Magazine, 

 and whose account, as illustrative of a remarkable pe- 

 culiarity in the economy of the insects of this family, 

 we here insert: "On a fineevening, towards the latter 

 end of May, I was collecting in the neighbourhood 

 of Brixton, near some ponds, when I was suddenly 

 covered by a multitude of small species of ephemera. 

 They settled on me, apparently from my being the 

 most conspicuous object near, on which to undergo 

 their final transformation. Their colour was of a 

 dusky white and opaque. They retained their posi- 

 tion, without moving, enabling me to observe be- 

 neath the glass the process by which these fragile 

 creatures withdraw themselves from the comparatively 

 cumbrous garment which envelopes their beautiful 

 and aerial form. Immediately on settling, the wings 

 were laid flat at right angles with the body, and the 

 insect remained about half a minute in a state of 

 repose. A slight motion then appeared about the 

 basis of the wings, which gradually collapsed, and 

 were drawn alongside the abdomen. At this mo- 

 ment the insect resembled a piece of dirty cotton- 

 wool, with little form. The elevated portion of the 

 thorax now distended, and then gave way longitudi- 

 nally, exhibiting the bright brown thorax of the 

 insect, which was vapidly followed by the head and 

 anterior legs. After this effort, the insect rested a 

 few seconds. The next discernible motion was in 

 the two or three last segments of the abdomen, where 

 the muscle* were in violent agitation, evidently for 



the purpose of extricating the fine setae which adorn 

 that part. The contractions continued upwards, and 

 the wings, freed from their flimsy covering, were fully 

 developed, and in an instant the delivered captive took 

 its flight ; the whole process strongly resembling the 

 drawing off of a tight glove. The whole operation 

 did not, in most cases, exceed three minutes ; in some 

 cases less. Scarcely an instant elapsed between the 

 full development of the insect and its taking flight, 

 so rapidly did they acquire consistency. I a some 

 few instances I observed them coupled, in which 

 case they soon died. I made a dozen or so find 

 their way into a phial ; they instantly deposited their 

 eggs, and died ; one only, which I believe was a male, 

 survived when I reached home, less than one hour 

 after. 



" The number of the insects was truly surprising, 

 they covered every part of my apparel, and my face 

 and hands were not exempt. On my arrival at home, 

 my hat looked like a millers, from being completely 

 covered with exuviae. I had taken several of these 

 insects during the evening, and had put them into 

 pill boxes ; almost all, however, were immature, and 

 died without undergoing their metamorphosis, from 

 which it would appear that light and a free atmos- 

 'phere are essential to its accomplishment. The 

 principal swarm, however, appeared about an hour 

 before sunset, and enjoyed their hour's existence in 

 one of the finest sunsets of this glorious summer." 



The singular circumstance of these insects under- 

 going a shedding of the outer skin, after they have 

 arrived at their winged state, is an apparent excep- 

 tion to the general rules of insect metamorphoses. 

 It is, however, to be observed, that many insects 

 appear, on bursting from the pupa state, to be enve- 

 loped in a delicate membrane, which is immediately 

 burst and thrown off. This has been often observed 

 by persons who rear lepidopterous insects, and it 

 appears to us that this envelope of the ephemera is 

 perfectly analogous to the pellicle of the moth, being 

 however, from its former consistence, retained longer 

 by the insect. 



On arriving at the perfect state, the only operation 

 which these insects have to perform is the propa- 

 gation of their race, the imperfect and rudimental 

 structure of the mouth preventing their taking any 

 nourishment in this state. The female, immediately 

 after impregnation, deposits her eggs in a mass in the 

 water. 



But although the may-fly lives only a very short 

 time when it has attained the winged state, its exist- 

 ence in the larva and pupa states has been much 

 longer, sometimes lasting even two or three years. 

 During this period it resides in the water, often con- 

 cealed during the day beneath stones or in holes, and 

 sometimes in horizontal burrows divided internally 

 into two canals, each having its own orifice. These 

 jurrows are always formed in clayey soils, covered by 

 :he water, which penetrates its cavities, and it has 

 Deen supposed that it is upon this soil that the larva 

 'eeds. These Iarva3 differ from the perfect insect, not 

 only by being destitute of wings, but in several other 

 particulars. The antennae are longer, the simple 

 yes are wanting, the mouth is provided with a pair 

 of corneous jaw-like appendages, the abdomen is 

 urnished on each side with a series of leaf-like plates, 

 ordinarily disposed in pairs, at the base of which 

 are a kind of false branchiae or gills, upon which the 

 racheas are laid out in a branching direction, and 



