1. _succincta_, Linnæus, ♂ ♀. 3½-5½ lines. _succincta_, Kirby. _fodiens_, Curtis. 2. _fodiens_, Kirby, ♂ ♀. 3½-4½ lines. _pallicincta_, Kirby, ♀. 3. _marginata_, Linn., ♂ ♀. 3-4 lines. 4. _Daviesiana_, Kirby, ♂ ♀. 3½-4½ lines. (Plate I. fig. 1 ♂ ♀.) GENERAL OBSERVATIONS. This genus is named from _κολλήτης_, _one that plasters_, in allusion to the habits of the insects, which will be described below. The female insects themselves have, at the first glance, very much the appearance of the working honey-bee, but they are considerably smaller, and, upon a very slight inspection, they are found to be exceedingly distinct. The respective males of the species are conspicuously smaller than their females, but their specific characteristics are very much alike, and there is some difficulty in separating and determining the species. One strong peculiarity, marking all of them, is that the segments of the abdomen are banded with decumbent, hoary or whitish down, in both sexes, and the determination of the species lies chiefly in the variations of these bands, and in the almost entire absence or conspicuous presence of minute punctures covering the segments. The females are very active collectors of pollen, and return from their excursions to obtain it, very heavily laden to their nests. I am not sure that all the species are not gregarious, to use this term in an acceptation somewhat different from its usual application, for here, and whenever used in entomology, it is meant to signify that they burrow collectively in large communities, forming what is called their metropolis, although each bores its independent and separate tube, wherein to deposit its store of eggs. The males, neither in these insects nor throughout the whole family of the bees, participate at all in the labours required for the preservation and nurture of the progeny, a duty that wholly devolves upon the maternal solicitude of the female,—these males having fulfilled their mission, which is not perhaps restricted to their sexual instinct, but may also be conducive to the grand operation of the family in the economy of nature, viz. the fertilization of the flowering plants, flit from blossom to blossom, and thus convey about the impregnating dust. They may also be often seen basking in the sunshine upon the leaves of shrubs, and thence they become lost or dispersed or the prey of their many enemies,—birds or insects, which are always on the alert in search of ravin.