From the extreme rarity of the insect, I have been unable to examine the cibarial apparatus, and thence to ascertain upon what substantial grounds the generic distinctions are based, which separate it from _Osmia_. Whether it was these mere habits of the insect which induced Le Pelletier de St. Fargeau to establish the genus I do not know, but he is always extremely slovenly, and therefore very unsatisfactory in his characteristics, which are never framed in a strictly explicit manner. In consequence of all these difficulties, I have merely been able under the generic character to introduce such as he has given, which I could not derive from the personal external inspection of Mr. Desvignes’ female (my own selection of whose bees for the purposes of this work he has been so kind as to lend me, and whom I thus publicly present with my best thanks). I have therefore compounded a character as well as I could from St. Fargeau’s descriptions, inserted in the tenth volume of the ‘_Encyclopédie Méthodique_,’ and from his work on the _Hymenoptera_, forming one of the ‘_Suites à Buffon_.’ The habits of these bees, as said above, are to excavate vertical cylinders in hard down-trodden pathways and roads, by the sides of fields where corn is grown, and where consequently the common red poppy is abundant. From the petals of the flowers of this plant they cut out semicircular pieces, precisely as is done by _Megachile_ with the more rigid leaves of shrubs and trees, and convey them home and line their nests with them, just as is practised by that genus with those leaves,—with this difference merely, that a sufficient portion of the upper edge of the pieces of the petals used is left projecting, for the purpose of forming a covercle to the nidus, and which, when filled with provender and the egg deposited, is refolded over it and covered in, and it is closed up with earth. They then proceed to make another excavation, which is treated in the same manner, for they deposit only one larva in a tube. If disturbed in their retreat, they will show themselves at its mouth, like _Dasypoda_, to see what is the matter. I would urge our collecting entomologists, especially those who have the opportunity of hunting up the west of England, to use due diligence and strive to confirm the native existence of this bee and add specimens to the cabinets of their fellow-entomologists. ------- Genus 24. OSMIA, _Latreille_. (Plate XIV. figs. 1 and 3 ♂♀.) APIS ** _c_ 2 _δ_, Kirby.