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