S2 HYMENOPTERA. 



menopterists a spot teeming with rarities in all the families 

 of the Aculeata. 



jSTearly sixty years have passed since the publication of 

 Kirby's " Monographia Apum Angliae," yet notwithstanding 

 the careful researches of subsequent Entomologists, some of 

 the species, founded upon the examination of one sex only, 

 have not yet been united to their legitimate partners ; there- 

 fore, every discovery that proves the identity of any two or 

 more thus constructed species, is, in my opinion, a great 

 boon to science ; it has been my good fortune to unravel one 

 or two of these Entomological enigmas. 



The appearance of an insect in large numbers year after year, 

 for a considerable period, succeeded abruptly by its almost total 

 extinction in the same locality, is one of a series of EntomiO- 

 logical phenomena of which we have little or perhaps no very 

 satisfactory knowledge. Arrested development, at some stage 

 of an insect's transformations, would apparently account for it, 

 to a certain extent, with some degree of satisfaction ; but when 

 it so happens, that the season of the insect's disappearance 

 was apparently in every respect highly favourable for its re- 

 iippearance, corresponding in fact with seasons in which the 

 insect was observed in the greatest abundance, then it is that 

 we are compelled to seek for causes in other directions, and 

 usually to conclude by confessing our ignorance, and our 

 inability to fathom the Infinite Wisdom that both regulates 

 the coming and the going of these His creatures. 



During the last twenty years I have assiduously searched 

 for aculeate Hymenoptera at Hampstead Heath, and in its 

 vicinity, and am consequently tolerably well acquainted with 

 the species inhabiting that locality ; but, alas ! it is one that 

 is being rapidly destroyed; the extension of the modern 

 Babylon will soon surround, if it does not spread over, that 

 richest of Entomological locations. But many rare species 



