HYMENOPTEKA-ACTJLEATA. 409 



and versicolor), in the mortar of old walls (M. 

 centuncularis M. maritima), and in sound oak and 

 mountain ash trees (M. lignesceca). Most of the 

 species, however, do not strictly confine themselves 

 to the above situations for nidification. The little 

 tunnels thus excavated they line in a remarkable 

 and beautiful manner with pieces of leaves or 

 flowers most accurately cut to the required size 

 and shape from various trees and shrubs, chosen 

 more or less according to species. No one " Leaf 

 cutter," however, confines itself to one particular 

 kind of plant, though the undermentioned have 

 been observed to be selected most frequently by 

 the following species, viz. : — 



Kose - - - by M . centuncularis, 



circumcinta, and 

 willughbiella. 



Mercury - - ,, M. centuncularis and 



circumcinta. 



Laburnum - - ,, M. centuncularis and 



willughbiella. 



Lilac - - - ,, M. centuncularis . 



Sallow - - - ,, M. centuncularis and 



maritima. 



Buckthorn - - ,, M. circumcinta. 



Scarlet geranium petals ,, M. centime ularis. 



Lotus corniculata petals „ M. argentata. 



The nests of the leaf-cutting bees are attacked 

 by the inquiline and nearly-related genus 

 Ccelioxys, and also by the Chalcid Monodon- 

 tomerus. 



M. maritima, Kirb. — lagopoda, Thorns. — Wallasey sand- 

 hills ; the Cheshire coast, B.C. ; not infrequent 

 in North Wales. 



