Named from _α_, privative, _πάθος_, _affection_; that is to say, without affection, from their habit of leaving their young to be nurtured by others, in allusion to their parasitical instincts, for the young of these bees are brought up in the nests of the _Bombi_. They form the only instance in bee-parasitism of the parasite closely, or nearly so, resembling its sitos, if not always in colour, certainly in habit. Having no labours to undergo they consist of merely males and females, but the latter, although very like the large female _Bombi_, are much less pubescent than these, for they have a broad disk, upon the upper surface of the abdomen, always smooth and shining. Both sexes appear to have free in- and egress to the nests of those _Bombi_ which they infest, without any let or hindrance on the part of the latter, with whom they seem to dwell in perfect amity. In the times of their appearance they closely resemble the _Halicti_ and the neighbouring _Bombi_. Thus the females, after impregnation in the autumn, having hibernated during the winter in selected receptacles, come out with the first gleams of spring conjunctively with the large maternal _Bombi_, in whose nests they have taken their long repose in perfect torpidity; and as soon as these begin to accumulate the masses of conglomerated honey and pollen whereon to deposit their eggs, the parasite takes advantage of it, lays her eggs too, and thus secures food for her offspring. There being two broods of them in the year, many are gradually developed with the advance of summer, but the great hatching takes place in the autumn, when the thistles are in blossom. Then both males and females come forth in abundance, the latter are made fertile, and their partners enjoy the brief interval of the still blossoming flowers until the usual period is put to their existence by natural decay, the first frosts, or the rapacity of insectivorous birds. Connected with this last circumstance I have a personal experience to record, and which its repetition would indicate as being one of Nature’s prompting acts. A lofty sandy level, very near the high-road which leads at the upper part of Hampstead Heath, to Highgate, from which road it was separated by merely a band of whins and coarse grass, used to be a very favourite collecting place of mine, for there, and in its immediate vicinity, I have often caught, within a very brief period, more than half the genera, and a very large number of the species of the fossorial _Hymenoptera_. One particular little spot was inhabited by _Psen equestris_, rare everywhere else, and our largest _Cerceris_, who carried on their instinctive pursuits during all the summer months, but at a particular time in the autumn, varying slightly with the nature of the season, a flock of wagtails (_Motacilla_) would alight and make brief work of those fossores which were still aflight; and this was repeated season after season, as if the