414 OBSERVATIONS ON INSECTS AND VERMES. 



in bulk, dart and shoot along on the surface of the water with the 

 males on their backs. When a female chooses to be disengaged, 

 she rears, and jumps, and plunges, like an unruly colt ; the lover 

 thus dismounted, soon finds a new mate. The females, as fast as 

 their curiosities are satisfied, retire to another part of the lake, 

 perhaps to deposit their foetus in quiet ; hence the sexes are found 

 separate, except where generation is going on. From the multi- 

 tude of minute young of all gradations of sizes, these insects seem 

 without doubt to be viviparous. WHITE. 



PHAL^ENA QUERCUS. 



Most of our oaks are naked of leaves, and even the Holt in 

 general, having been ravaged by the caterpillars of a small 

 phalana 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 at Greatham, I saw a flight of swifts busied in catching 

 their prey near the ground \ and found they were hawking after 

 these phalcencz. The aureltce 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 phafana 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 num- 

 ber 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 exuvitz or remains of the chrysalis, from whence 



