102 HYMENOPTERA 



Antennae scarcely longer tlian the head. Crabronidce. 

 Antennae much longer than the head. 



Posterior tibife spinose or toothed. Pompilidce. 



Posterior tibiae not spinose. Thynnidce. 



Tamilt— CRABRONID^. 



Mandibles not notched interiorly. Labium shorty either dilated at 

 its extremity^ or composed of three equal diA'isions. Maxillary palpi 

 six-jointed ; labial palpi four-jointed. Antennae shorter than the head 

 and thorax. Fore wings narrow. 



A. Abdomen ovoid-conical ; head moderate. 



Middle tibiae with a single spine at the apex. Larrinoi. 

 Middle tibiae with two spines at the apex. Nj/ssoninae. 



B. Abdomen oval or elliptical ; head large. Crabronince . 



Sub - Family — Laeeinj3. 



Genus-TACHYTES. 

 Panzer. 



Head transverse^ wider than the thorax; the mandibles large, 

 arcuate and acuminate, within bidentate, deeply emarginate on the 

 exterior towards the base, or notched, forming a dentate process. 

 Thorax ovate ; the prothorax almost concealed beneath the convex 

 gibbosity of the mesothorax ; metathorax short, rounded at the sides, 

 gradually declined above to the apex, not sharply truncated, as broad as 

 long ; the superior wings, with one marginal cell, more or less rounded 

 at the apex, not truncated ; three submarginal cells, the second 

 receiving both recurrent nervures. Abdomen short, ovate-lanceolate, 

 subsessile, not longer than ' the thorax, usually subdepressed above ; 

 the apical segment with the disc flat, the margins reflexed. 



T. NiGERRiMUs. Siuith, Cat. Hijmen. Brit. Mus., Pi. IV., p. 302 



(1856) . 



Female. Intensely black and shining, the face with a thin silvery 

 pubescence ; the clypeus rounded anteriorly and emarginate in the 

 middle. The mesothorax and scutellum sparingly and delicately 

 punctured ; the metathorax truncate behind, finely shagreened and 

 opaque ; the truncation transversely striated, the sides obliquely so ; 

 the wings hyaline, the nervures black, the marginal cell without an 

 appendage at the ajiex, having merely a fuscous line. Abdomen short 

 and conical, very smooth and shining. 



Length, 5 2 lines. 



