OB SEE NATIONS ON INSECTS AND YERMES. 339 



separate, except where generation is going on. From the 

 multitude of minute young of all gradations of sizes, these 

 insects seem without doubt to be viviparous. WHITE. 



PHAL.&NA QUERCUS. Most of our oaks are naked of 

 leaves, and even the Holt in general, having been ravaged by 

 the caterpillars of a small pfialasna, which is of a pale yellow 

 colour. These insects, though a feeble race, yet, from their 

 infinite numbers, are of wonderful effect, being able to 

 destroy the foliage of whole forests and districts. At this 

 season they leave their aurelia, and issue forth in their fly 

 state, swarming and covering the trees and hedges. 



In a field near Greatham I saw a flight of swifts busied in 

 Batching their prey near the ground ; and found they were 

 hawking after these phalaence. The aurelia of this moth is 

 shining, and as black as jet ; and lies wrapped up in a leaf of 

 the tree, which is rolled round it, and secured at the ends by 

 a web, to prevent the maggot from falling out. WHITE. 



I suspect that the insect here meant is not the phalcena 

 quercus, but the phalcena viridata, concerning which I find 

 the following note in my Naturalist's Calendar for the year 

 1785 :- 



About this time, and for a few days last past, I observed 

 the leaves of almost all the oak trees in Denn copse to be 

 eaten and destroyed, and, on examining more narrowly, saw 

 an infinite number of small beautiful pale green moths flying 

 about the trees ; the leaves of which, that were not quite 

 destroyed, were curled up, and withinside were the exuvice, 

 or remains, of the chrysalis, from whence I suppose the moths 

 had issued, and whose caterpillar had eaten the leaves. 



MARKWICK. 



EPHEMERA CATIDA. BISETA (MAT ELY).* June 10, 1771. 

 Myriads of May flies appeared for the first time on the 



* The most extraordinary appearance of May flies I ever witnessed was on 

 the Colne at Denham near Uxbridge, the hospitahle seat of the late John Drum- 

 mond, Esq. The air was full of them, and the water covered by them. The 

 whole scene was equally beautiful and surprising, and I have no doubt but that 

 my old angling-friend, Richard Penn, Esq., will recollect the day aud the 

 occurrence. ED. 



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