278 THE ENTOMOLOGIST. 



a species of insect, the ordinary number of individuals of 

 which in a given copse would be a hundred pairs; that the 

 pairing time is so favourable that twice the average number 

 of eggs is laid; and that, owing to a scarcity of birds, or to 

 very genial weather prevailing, only half the usual number of 

 young larvae die ; the result will be that the next generation 

 would consist of four hundred pairs : suppose all this hap- 

 pened to that generation also, then the numbers in the fol- 

 lowing generation would be swollen to sixteen hundred pairs ; 

 and all this, in double-brooded insects, might happen in a 

 single year. Suppose now that the next generation comes to 

 maturity in weather so unfavourable that only one-fourth can 

 find suitable mates, and that, when the eggs laid by this pro- 

 portion hatch, a spring frost comes and kills seven-eighths 

 of the young larvae, with the leaves they are feeding on ; this 

 would bring down their numbers to fifty; and a concurrence 

 of similar causes, during the next generation, might reduce 

 the sixteen hundred pairs to six pairs in the space of a 

 single year. One other cautionary suggestion, and I have 

 done. Scarce insects must be far more numerous than the 

 number of them captured would lead one to suppose. Con- 

 sidering how small a proportion the field searched by ento- 

 mologists bears to the whole country over which the insect 

 ranges, and how large a number in the hunted district must 

 escape observation, a species, the captures of which are 

 recorded in units, must exist in many thousands, probably 

 often in millions. — F. Merrijield ; Brighton, May 19, 1869. 



Orgyia antiqua. — In your ' Illustrated History of British 

 Moths,' page 40, I notice a remark on the lengthened period 

 over which the hatching of a brood of Antiqua eggs extends, 

 and that Quartermaster-Sergeant M'Laren is credited with 

 the discovery of this interesting fact ; but if you refer to the 

 ' Entomological Magazine,' vol. ii. page 318, you will see 

 that the gallant soldier's observation has been anticipated 

 by Mr. Jas. Fennell thirty-five years since. — E. Birchall ; 

 April 20, 1869. 



Extraordinary Vitality of a Pupa. — Early in January of 

 this year an intimate friend of mine brought me a pupa 

 which his cook had taken out of the craw of a pheasant, 

 together with several acorns and other food, the pheasant 

 having been hung in his larder for nearly three weeks. As 



