Mason-Bees. 41 



of the aphis. Some of them haunt the galls, and contrive to 

 make their young parasitic upon the immature cynipidse 

 which lie within the gall. The common small tortoise-shell 

 butterfly is terribly infested with these little creatures, and 

 we have bred hundreds of the gem-like Ckalcididce from the 

 larvae and pupae of that butterfly. 



One of the Chalcididce, belonging to the genus Melittolia, is 

 a parasite upon the Aniliophora ; and the curious part of the 

 proceeding is, that it finds there another parasite, which 

 becomes developed in the home of the bee : the Melittobia 

 feeds indiscriminately upon the bee and parasite. 



Although the Melittobia does not make such wholesale 

 destruction as is wrought by the earwig when it gets into a 

 nest, it does more damage to the bee, on account of its great 

 numbers. Some three or four females will lay a great 

 quantity of eggs within a nest, and from those eggs a hundred 

 of the young will be developed. When the larvae are fully 

 grown, they quit their hold of their prey, and fall to the 

 bottom of the cell, where they lie until they have assumed 

 the perfect form. They then burst forth, together with those 

 of the bee that may have escaped their attacks.] 



An interesting account is given by Reaumur of another 

 mason-bee (Megachile muraria), not a native of Britain, select- 

 ing earthy sand, grain by grain ; her glueing a mass of these 

 together with saliva, and building with them her cells from the 

 foundation. But the cells of the Greenwich Park nest were 

 apparently composed of the mortar of the brick wall ; though 

 the external covering seems to have been constructed as 

 Reaumur describes his nest, with the occasional addition of 

 small stones. 



About the middle of May, 1829, we discovered the mine 

 from which all the various species of mason-bees in the 

 vicinity seemed to derive materials for their nests. (J. R.) 

 It was a bank of brown clay, facing the east, and close by the 

 margin of the river Ravensbourn, at Lee, in Kent. The 

 frequent resort of the bees to this spot attracted the attention 

 of some workmen, who, deceived by their resemblance to 

 wasps, pointed it out as a wasps' nest ; though they were not 



