322 



VARIETIES. 



accommodating provision, which is so often most beautifully 

 illustrated in the habits of insects ? c 



Denmark Hill. G - MoORE. 



19. Metamorphosis of Ephemera. — On a fine evening, 

 towards the latter end of May, I was collecting in the neigh- 

 bourhood of Brixton, near some ponds, when I was suddenly 

 covered by a multitude of a small species of Ephemera, — I 

 think the genus Cloeon. 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 position without moving, 

 enabling me to observe beneath the glass the process by which 

 these fragile creatures withdraw themselves from the compara- 

 tively 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 bases of the wings, which gradually collapsed, and 

 were drawn alongside the abdomen. At this moment the 

 insect resembled a piece of dirty cotton wool with little form. 

 The elevated portion of the thorax now distended, and then 

 gave way longitudinally, exhibiting the bright brown thorax of 



c The Chelifer cancroides is very abundant throughout the year on planks and 

 bricks that are placed on decayed vegetable matter, where it preys on minute 

 Diptera, (Molobrus, Scatopse, Sfc.) Loncheea vaginalis, a fly common in the same 

 situations during the month of June, is particularly infested by it, and also by 

 Acari, and may be often seen on windows with from one to four Cheltferi attached 

 by the claw to its trochanteres, and apparentlv without sustaining any injury 

 from them. The other day we put several of both into a bottle, and often, when 

 the fly approached the Chelifer, the latter immediately extended one of its claws, 

 and seized the fly by the end of the tarsus ; with the other claw it grasped either 

 the middle of the tarsus, or the costal nervure of the wing, and then loosened the 

 hold of each of its claws alternately till it arrived at the trochanter, where it 

 remained fixed. We added three other flies, belonging to the genera Anthomyia, 

 Sepsis, and Borborus. The first, a much more active insect than the Loncheea, 

 was soon seized by a Chelifer. It used its utmost eflbrts to disengage its tarsus 

 without success ; however, the Chelifer soon relaxed its hold of its own accord. 

 "When we looked at the insects the following day, the Loncheea, the Anthomyia, 

 and the Borborus were alive, and only the first had a Chelifer attached to it ; so, 

 likewise, had the Sepsis, whose death was probably occasioned by confinement! 

 not by any wound. — En. 





