Thus the first species, the _O. leucomelana_, named so from the white decumbent down which edges the black segments of the abdomen, extracts the pith from bramble sticks, and its cells are formed and closed with a composition made of triturated wood or leaves. The cylinders it forms are usually about five inches deep, and within this it constructs about the same number of cells proportionate to the small size of the insect. These are midsummer insects, coming forth in June and July; they are very local, but seem to abound in the vicinity of Bristol, whence Mr. Thwaites formerly sent me specimens. A very few days serve for the hatching of the larva, which spins a slight silken cocoon, and in this dormitory it reposes until its season again comes round. Under the influence of the following first genial spring weather, the larva is transmuted into the pupa, and the active little imago comes forth upon the settlement of our variable spring, in the merry days of June, and thus is perpetuated the circle of its existence, but which is sometimes abridged by its special parasite, the pretty little _Stelis octomaculata_. Many of the species in the males are distinguished by a peculiar armature of the apex of the abdomen; the second being named by Kirby from the circumstance. A very remarkable singularity distinguishes the males of the third species, in the fringe of short hair that runs along the flagellum of its antennæ. This, I believe, was first noticed by the late Mr. Bainbridge, a very active practical entomologist, who took the insect at Darenth or Birchwood, and distributed specimens with this manuscript name attached, which has since been appropriated by another entomologist to whom the science was wholly unknown at that time, but as it is scarcely consistent with scientific courtesy to adopt such a course, and as the MS. names of Linnæus and Kirby have been retained, where it was authorized by their being attached to undescribed species, I have restored to Mr. Bainbridge his just rights, and have claimed the same for myself, in the case of _Andrena longipes_, and which many cabinets must still possess with my name attached, in my own writing, unless their possessors have chosen to adopt the illegitimate parentage; for the entomologists of my own standing well know that I always freely distributed specimens to all who desired them of the many very desirable insects which I have captured in the course of my entomological career. The fourth and the ninth species, the _O. bicolor_ and _O. aurulenta_, have very much the same habits, both usually burrowing in sandbanks, sometimes however in wood, in which case the perforation, contrary to the mode of wood-drilling bees, is made upwards, a sagacity or instinct which saves it much trouble, for the particles as they are removed by the mandibles are passed beneath the insect, and their own gravity carries them downwards, and thus the insect saves itself the labour of conveying them out as they accumulate