Dec. 1896.] Packard: Transformations of Hymenoptera. 157 



testaceous or chitinous line, opposite and just within the lower end of 

 which are situated the antennal rudiments, situated in a round depres- 

 sion. Supraclypeal piece obscurely marked at the base. Clypeus sub- 

 trapezoidal, angular in the middle on each side ; twice as broad as long ; 

 base and front edge transverse, the front edge slightly concave, exserted 

 so as partially to envelop the base of the mandibles. Labrum very free, 

 exserted and overlapping the mandibles ; more than twice as broad as 

 long, bilobate, the corners rounded, the front edge excavated ; thin, 

 transluc*ent. Mandibles short, twice as long as broad at base, triden- 

 tate, the mesial tooth largest, the inner smallest. Maxillse rather long 

 and slender. Rudiments of the palpi acute, longer and more pointed 

 than usual. Labium a little wider than usual, the rudiments of the 

 labial palpi acute. Body long cylindrical, the segments of uniform 

 size and shape, not thickened much behind, but still as much so as in 

 the larva of Megachile, for instance, and in this respect very different 

 from Crabronid and Pompilid larvae. The pleural region is not promi- 

 nent. The body is very cylindrical ; the tip broad obtuse, the terminal 

 tergites and sternites broad and flat, together forming an orbicular area, 

 very different from the exserted prominent knob-like ending of the 

 larva of Pompilus. 



It differs from the larva of Pompilus in the short curvilinear tes- 

 taceous line, in the short broadly trapezoidal clypeus and the distinct 

 exserted labrum. The mandibles differ from those of Pompilus in be- 

 ing tridentate and twice as long. The front edges of the segments 

 are thickened, but not so convex as in Pompilus, giving a serrate ap- 

 pearance to the body. Tip rounded, full, not nearly so acute as in 

 Pompilus. The larvae of the two genera differ greatly; indeed, more 

 than one would suspect, considering that they are representatives of two 

 allied families. 



Pelopasus cementarius {Drury) (flavipes Fa/>r.). 



Pupa. — The pupa of PelopcBus differs from that of Polistes and 

 Vespa in the head being raised more from the pectus. The palpi are 

 visible along their whole length. The legs are much longer, and the 

 pedicel is of the same shape as in the adult. The head is much as in 

 the imago. The mandibles long, slender, curved, covering the base of 

 the maxilla and lingua. The scape of the antennae is oblique ; the 

 flagellum reaches to the posterior coxae, resting between the two anterior 

 pairs. The maxillae are slender, not reaching to the entire labium. Of 

 the rhabdites or blades of the ovipositor, only one pair is visible ; the 



