OF HARTING. 385 



have not had the opportunity of identifying, but we 

 have taken many of these pretty wasp-like flies, among 

 others Nomada Marshamella, Nomada rufiventris, 

 Nomada ruficornis and Nomada flava. As they are 

 unprovided with apparatus for carrying pollen, they 

 are supposed to have a cuckoo-like connection with 

 other bees, probably Andrena, depositing their eggs 

 in the pollen paste collected by the latter, and thus 

 avoiding the labour of constructing nests of their own. 

 The Leaf-cutter bees form their burrows in decayed 

 wood, and that of Megachile centuncularis, an insect 

 also resembling the Hive-bee, we once discovered in 

 an old gate-post in Hotston Paddock. It was eight 

 or ten inches deep, and when laid open, disclosed a 

 leafy tube accurately fitting the interior. On ex- 

 amination we found that this tube was formed of 

 distinct cells, one above the other, the bottom of each 

 cell closing the mouth of the one below it, and all 

 filled with a thick dark coloured honey or pollen 

 paste. We have often seen these bees during their 

 nidification, engaged on different plants in the shrub- 

 bery, the rose especially and the laburnum. The 

 insect fixes itself on the edge of a leaf, holding it on 

 each side between its legs, and with its sharp man- 

 dibles clips out a circular piece so accurately, that 

 when it has removed it, the leaf has the appearance of 

 having had a neat little disk punched out of it, some- 

 what larger than the top of an ordinary thimble. If 

 undisturbed in this operation, it proceeds very quickly 

 without hesitation or pause, till it has accomplished 

 its purpose, when it immediately takes wing and 

 disappears with its load, still holding it between its 

 legs. These circular disks are intended for the 

 bottoms of the cells, the sides of which are formed of 

 larger pieces of a different shape, principally oval. 

 It will be evident that a considerable interval must 

 elapse between the deposition of the first egg in the 

 lowest cells of the series, and that of the last in the 



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