The peculiarity of these spines at the apical segments of the abdomen of the males is remarkable, they being straight projecting processes, or they have even a slight upward bearing. In the males of _Anthidium_ and _Osmia_ we observe spines also arming the apex of the last segment, but in these we can trace an evident use, both from the downward curvature of the abdomen itself, and that same tendency also in the spines. But in the insects of this genus they have not the same conspicuously apparent object, the abdomen itself even having an upward curvature, or rather a greater facility for turning upwards than downwards. These insects appear to be most abundant in the midland and southern counties, and, according to Curtis, they are numerously found at the back of the Isle of Wight. I have usually taken them on the wing and never on a flower, and I do not know the plants which they may prefer.
Subsection 3. DASYGASTERS (convey pollen on the belly). _All with two submarginal cells to the wings._ Genus 19. MEGACHILE, _Latreille_. (Leaf-cutters.) APIS ** _c_ 2 _α_, Kirby. (Plate XII. fig. 2 and 3 ♂♀.)
_Gen. Char._: HEAD as wide as the thorax, flat and broad on the _vertex_, where, on the anterior edge, the _ocelli_ are disposed in a triangle; _antennæ_ shortish, filiform, geniculated; _scape_ about as long as two first joints of flagellum, which increases both in length of joints and their substance from base to apex, the terminal one being the longest, and longitudinally compressed; _face_ and clypeus very pubescent, concealing their divisions; _clypeus_ transversely lunulate, scarcely convex; _labrum_ longitudinally slightly convex and oblong, with the sides parallel; _mandibles_ broad, widening outwardly, irregularly quadridental, the two inner teeth obtuse; _cibarial apparatus_ moderately long; _tongue_ more than twice the length of the labium, tapering from the base to the apex, where it terminates in a minute knob; _paraglossæ_ very short, scarcely one-sixth the length of the tongue, coadunate at the base and acuminate at the apex, where, in repose, they lap round the base of the tongue; _labial palpi_ three-fourths the length of the tongue, the two basal joints long, subequal, membranous, linear, slightly tapering to the acute apex of the second, where the third subclavate joint articulates just before its termination, and conterminous with which is the fourth, shorter than the third, but also subclavate; _labium_ not quite half the length of the tongue, with a long subobtuse process in the centre of its inosculation; _maxillæ_ subhastate, and very acuminate, nearly as long as the tongue; _maxillary palpi_ very short, two-jointed, the basal joint the shortest, and the terminal one obtuse at its apex, where it is furnished with brief setæ. THORAX subglobose, pubescent, the pubescence almost concealing its divisions; _prothorax_ inconspicuous; _mesothorax_ convex, subglabrous on the disk; _scutellum_, lunulate, convex; _metathorax_ truncated; wings with two submarginal cells, the commencement of a third slightly indicated, the two complete ones nearly equal, the second of which receives both the recurrent nervures, one towards each extremity; _legs_ robust, very setose; the posterior _tibiæ_ slightly curved longitudinally, concavo-convex, broad at the extremity; all the _plantæ_ as long as their tibiæ and as broad at the base but decreasing at the apex to the width of the following tarsal joints, the anterior pair fimbriated externally, and the posterior pair clothed, on the inner surface, with a dense, short brush, the three following joints short, subequal, the claw-joint as long as the three, and the _claws_ with a broad basal inner tooth. ABDOMEN ovate, with parallel sides, convex above, truncated and concave at its base to fit the metathorax, distended horizontally in length, or with an upward curve, the four first segments slightly constricted, and their edges usually clothed with decumbent down; the terminal segment obtusely pointed and slightly depressed transversely towards its extremity; the _ventral segments_ commencing with the second, clothed with parallel layers of moderately long, straight setæ, which in each parallel are of equal length, but those on the fifth segment are the shortest, upon all of which the insect conveys the pollen it collects.
