HISTORY OF THE EUMENES. 481 



opening having a recurved lip. As a rule, the insect manages 

 to preserve the spherical form of its nest, no matter what may 

 be the exigencies of the locality. The nest is stocked with 

 caterpillars, mostly belonging to the Geometridse, and almost 

 invariably green in colour. 



As is often the case with solitary wasps and bees, the 

 Eumenes is liable to the attacks of parasites, of which the 

 ubiquitous Euby-tail {Chrysis) is sure to be one. Mr. Home 

 mentions one very remarkable instance of parasitic develop- 

 ment. From a single cell of Eumenes esuriens the insect was 

 hatched in due course of time. But there was also hatched a 

 beetle belonging to the genus Emanadia. This insect is allied 

 to our Sitaris muralis, which is so well known to entomologists 

 as being parasitic on various solitary bees. Besides this, a fly, 

 apparently belonging to the genus Anthrax, was hatched from 

 the same nest. Now, the wonder is, how all these insects con- 

 trived to obtain sufficient food when packed within so narrow a 

 compass, especially as the fly is not a small one, and the beetle 

 is fully three-quarters of an inch in length. Had the beetle or 

 the fly appeared instead of the Eumenes, there would have been 

 nothing strange ; but that all these should appear, and be fully 

 developed, is an absolute mystery. 



The Anthrax, by the way, is a very troublesome insect to the 

 Eumenes, as well as to other solitary Hymenoptera. Generally, 

 after a cell is closed it is tolerably safe, but the Anthrax con- 

 trives to pierce through the covering of the cell, and so to 

 deposit an egg. The reader will therefore understand how 

 difficult is the task of identifying the builder of a nest when, 

 instead of an Eumenes or Pelopseus, an Anthrax, a Chrysis, 

 or an Emanadia may emerge, and sometimes two or three 

 at once. 



Mr. Home further remarks that it is very rare to find a nest 

 from which the Eumenes has escaped, unless it be perfectly 

 empty and affording no clue as to the habits of the occupant. 

 This is due to the ants, who swarm in India and are ever rest- 

 less in search of food. As long as the mud-nest of the Eumenes 

 is closed, the ants cannot touch it, but no sooner does the newly 

 developed Eumenes leave its nest, than the ants pour into it 

 and carry off everything in it, not only the unconsumed cater- 

 pillars if there should be any, but the skins of those that have 



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