( xli ) 



with its naked, red abdomen, nests apparently in Helix aspersa : 

 from whence I have taken it seeking shelter. 



" Osmia versicolor, Latr., establishes itself in Helix nemoralis. 

 almost at the bottom of the spiral. 



" Osmia cyanea, Kirby [i. e. Osmia caerulescens, L.], appears 

 to me to accept very varied lodgings. I have taken it from 

 old nests of Chalicodome des galets [C. muraria], from galleries 

 excavated in banks by Colleles, and from holes made by some 

 unknown borers in dead willows. 



" Osmia morawitzi, Per., is not uncommon in the old nests 

 of Chalicodome des galets, but I suspect it of having other 

 lodgings. 



" Osmia tridentata, Duf. et Per., makes a dwelling for itself. 

 With the point of its mandibles it bores a channel in a dry 

 bramble, and sometimes in the elder [Sambucus ebulus]. To 

 the green paste it adds a few scrapings of the excavated pith. 

 Its methods are shared by Osmia detrita, Per., and Osmia 

 parvula, Duf." 



It would be of extreme interest to ascertain how far the 

 shell-using instinct follows other characters and whether it 

 is to be most reasonably explained by derivation from a 

 common ancestor. Taking Osmia as a whole it is at present 

 hopeless to attempt to estimate the proportions of the shell- 

 using species, but of the ten British species we find in the above 

 list records of the instinct in four. It is desirable to set down 

 the nidification, so far as it is known, of the remaining six : — 



1. Osmia caerulescens, L. " Posts, dead stumps, etc., 

 and commonly in the mortar of walls and mud- walls. ' Some- 

 times in hard sandbanks ' fide Smith. R. C. L. P." 



" Nests in old posts, choosing a ready-made hole, when 

 available. A. H. H." 



2. Osmia inermis, Ztt. (parietina, Smith, Saund., etc.). 

 " The cocoons of this species, according to Smith, are attached 

 to the lower surface of stones which have a hollow space 

 beneath them, he once had a stone with 230 cocoons under 

 his observation, the bees from some of the cocoons did not 

 emerge for three years after the stone was found " (Saunders, 

 - Hymenopt. Acul. Brit. Isles," 1896, p. 334). 



