b. _Cruriferæ_ (collectors on the shank only).
Subsection 3. DASYGASTERS (hairy-bellied).
Section 2. _Cenobites_ (Dwellers in Community).
The primary division of the bees into two large branches, viz. into the _Andrenidæ_, or abnormal bees, and the _Apidæ_, or normal bees, is effected by the mode in which they fold the cibarial apparatus in repose. In the description of the structure of the imago, I have enlarged upon these organs, and for their explanation I must refer to that chapter where diagrams exhibit the structure of the different kinds of trophi of the bees, as well as their mode of folding. Here it is only necessary to notice that in the _Andrenidæ_, the joint at the base draws back the basal portion when protruded, and this basal portion is further jointed at the point of the insertion of the paraglossæ and labial palpi, and parallel with which joint the maxillæ are likewise jointed close to the sinus where the maxillary palpi are inserted laterally upon it. The basal portion thus throws the anterior part forward or retracts it, at the will of the insect, and in the latter case, being then in repose, it lies in contiguous parallelism to the basal half, but beneath it. When thus withdrawn, the short tongue itself, with its paraglossæ and labial palpi are sheltered beneath the coping of the labrum and the lateral protection of the mandibles, whilst the horny sheathing of the maxillæ protect the softer parts folding underneath.
In the _Apidæ_, or normal bees, the basal joint has the same action in withdrawing the entire organ into its place of rest; but the joint which gives it this power is not in an analogous situation to that in the _Andrenidæ_, for it is seated short of the joint which lies at the base of the several organs of the cibarial apparatus. By bending these downwards, it carries their apex backwards towards the basal fulcrum through the action of these two joints, and, when there, the more delicate ones are protected from abrasion or injury, by the lateral overlapping of the horny skin of the maxillæ. All being thus withdrawn within this covering, upon the joint which folds them back, seated at the base of the tongue, the labrum falls, and further to strengthen this protection, the mandibles close over it like forceps.