Mr. Kirby could scarcely have considered that there were more than two series of equivalents in this scheme, the first being the great division into the two genera; and the second, the final division, where his analysis terminated in his families, which, with some further slight subdivision, as shown above, constitute our present genera. The synthetical combinations which the arrangement presents, as we ascend from his families, result from an almost arbitrary selection of characters and certainly are not equivalents. The whole method is very perplexing; for, to cite an insect for the purpose of making a communication, it would have to be preceded by its whole array of subdivisions. Thus _Megachile Willughbiella_, which is now so compendiously noticed by the binomial system, would have to be quoted as _Apis_ * * _c_, 2, _a_, _Willughbiella_, and so with the rest. Although I have strongly applauded the ‘Monographia Apum Angliæ,’ as an excellent treatise wherever I have had an opportunity, the praise is to be applied to the correct care with which both the family descriptions and the specific descriptions are elaborated; whilst Mr. Kirby’s timidity in fearing to depart from the course of his masters, Linnæus and Fabricius, by establishing a multitude of genera unrecognized by their authority, although every one of his families is pertinently a well-constituted genus, is much to be deplored. He has thus lost the fame of naming the offspring, of which, although legitimately the parent, he was not the sponsor. But he has won the higher renown, as I have elsewhere remarked, of his work being a canon of entomological perfection. Notwithstanding that this very elaborate, and, to some extent, artificial method is based upon a plurality of characters, and apparently upon such as most readily presented themselves to substantiate the feasibility of subdivision indicated by habit, it is very remarkable in having brought the series into more satisfactory sequence than that presented by Latreille and his modifiers. _Panurgus_ here holds its permanent post as the connecting link between the _Apidæ_ and _Andrenidæ_, pointed out by nature in its close resemblance to _Dasypoda_. But this genus, however, establishes for itself a stronger affinity to the _Apidæ_, exclusively of that presented by the folding of the tongue in repose, in its presenting immediately the large development of the labial palpi which is peculiarly characteristic of this subfamily. All the cuckoo-bees then follow in order; these are succeeded by the true _Dasygasters_; after which come Latreille’s _Scopulipedes_; and the series is wound up by _Apis_ and _Bombus_.