Xll DESCRIPTION OF THE COLOURED PLATES 



Fig. 11. Sphecodes subguadratus Smith: female; cuckoo of a 

 species of Halictus ; female hibernates like its host (p. 17). 



Fig. 12. Halictus lencozonius Schr. : burrows in the ground ; 

 the host of Sphecodes pilifrons Thorns (p. 17). 



Fig. 13. Vespa crabro L. : female (the Hornet), nests in 

 hollow trees ; host of the rare beetle Velleius dilatatus (p. 38). 



Fig. 14. Vespa vulgaris L. : female : one of our commonest 

 wasps ; nests usually in the ground (p. 35) ; host of a 

 peculiar beetle (Metcecus paradoxus (p. 38). 



Figs. 15, 16. Andrena fulva Schr. : male and female ; the bee 

 which burrows in lawns, etc. (p. 9); host of Nomada ruficornis 

 var. signata (p. 15). 



Fig. 17. Panurgus ursinus Gmel. : Female ; legs loaded with 

 pollen, burrows in hard sandy paths, etc. (p. 49). Males 

 sleep curled up amongst the rays of yellow composite 

 flowers. 



Fig. 18. Nomada ruficornis L. var. signata : cuckoo of Andrena 

 fulva (figs. 15 and 16). 



Fig. 19. Epeolus rufipes Thorns: female; cuckoo of Colletes 

 succinctus (fig. 10). 



PLATE C 



Fig. 20. Megachile maritima Kirby : female ; burrows in the 

 ground, makes its cells of pieces of leaves, which it cuts out 

 with its mandibles ; host of Ccdioxys conoidea. 



Figs. 21, 22. Ccdioxys conoidea Ittig : male and female ; cuckoo 

 of Megachile maritima. 



Fig. 23. Burrows of Megachile Willughbiella Kirby, in a piece 

 of rotten willow; each burrow originally contained six 

 cells, but two of the left-hand series have been lost. 



