is extended. Externally continuous, the line of these _maxillæ_ is broken at the point of flexure at the apex of the _labium_, by a deep sinus or curve, and within this is inserted the first joint of the maxillary palpi. The portion of the maxillæ extending forwards, hence takes several forms, usually tapering to an acute point, but sometimes rounded or hastate, according to the structure of the tongue, to which they form a protection. The _maxillary palpi_ are small, longitudinal joints, never exceeding six in number, and generally in the normal or true bees not so numerous. They vary in relative length to the organ to which they are attached, and usually progressively decrease in length and size from the basal ones to the apical, but each joint, excepting the terminal one, is generally more robust at its apex than at its own special base. The function of these maxillary palpi is unknown. They are always present in full number in the _Andrenidæ_, and in some few genera of the true bees, but they vary from their normal number of six to five, four, three, two, and one in the latter; and it is curious that they are most deficient in those bees having the most complicated economy, as in the artisan bees and the cenobite bees; they thus evidently show that it is not a very paramount function that they perform. On each side, at the apical summit of the _labium_, are inserted the _labial palpi_. These are invariably four in number, but vary considerably in length and substance. In the _Andrenidæ_ they have always the form of subclavate, robust joints, and are usually as long as the tongue, but not always; they are only half the length of that organ in the subsection of the acute-tongued _Andrenidæ_. In the normal bees, even in the genus _Panurgus_, which is the most closely allied to the _Andrenidæ_, the labial palpi immediately take excessive development, especially in their two basal joints, and the structure of these two joints, excepting in this genus and in _Nomada_, partakes of a flattened form and membranous substance. All these four joints are either conterminal, or the two apical ones, or one of them is articulated laterally, towards the apex of the preceding joint. These two are always very short joints, and are comparatively robust.