Sept. 1897] Packard: Transformations of Hymenoptera. 109 



NOTES ON THE TRANSFORMATIONS OF HIGHER 

 HYMENOPTERA— III. 



By a. S. Packard. 



Megachile (possibly centuncularis Linn.). 



Larva. — Head of the usual proportions, of good size compared with 

 the rest of the body. Eye-pieces prominent, full and convex. Towards 

 but below the vertex, in between the eye-pieces, is a depressed subcordate 

 area, with a subacute depressed tubercle on each side of the median 

 line, which may be the antennce; between this area and the clypeus is 

 a transverse raised portion ; on each side of this ridge and aligned with 

 the side of the labrum at its base is a minute corneous tubercle, which 

 may be the antennae, though I think not. 



The clypeus is considerably shorter than broad ; its base is a little 

 subacutely produced onesidedly, the front edge deeply excavated ; the 

 surface is not convex and increases in width towards the anterior edge. 

 The labrum is broadly subtrapezoidal, twice as broad as long ; base 

 rounded, semi-circular; anterior edge rather deeply excavated, render- 

 ing it slightly bilobate. Mandibles slender, not narrowing much towards 

 the end, which is unequally bidentate, the inner tooth the smaller; 

 they are much broader, stouter and thicker at the end than in Andrena. 



The maxillae are long and slender, acutely pointed at the tip on one 

 side, the inner lobe being produced and incurved, while the outer acute 

 lobe or tubercle is minute ; this is easily overlooked and more remote 

 from the other lobe than usual ; they are long enough to touch each 

 other. The labium is long, square at the end, corneous; below and 

 posterior to this square corneous or chitinous edge are two minute acute 

 spines on each side of the labium, which are probably the rudimentary 

 labial palpi. 



The body is thickest towards the posterior end, on the terminal fifth 

 of the body, whereas in Andrefia it is thickest at about the middle; 

 towards this last fifth the body gradually increases in thickness, and 

 then suddenly rounds off, so that the end is much rounder, more obtuse 

 than in Andrena and the larva of Apidae in general. The penultimate 

 sternite is larger and broader than in Andrena, while the last sternite 

 is smaller; differences readily appreciable. On the whole the larva of 

 Megachile resembles that of Bombics more than that of Andrena. 



As regards the head characters, the larval Megachile differs from the 



