CHARLES W. HOOKER. / 



bears no distinctive marks, but more or less evident tubercles 

 are sometimes present below or between the antennal fossae. 

 The clypeus is not separated from the frons above but at its 

 outer margin is a more or less distinct fovea, deep and oval 

 or sometimes shallow and more elongate, with a furrow ex- 

 tending from it to the base of the mandibles ; the anterior 

 margin of the clypeus is rounded, or somewhat pointed in 

 the middle. The mouth parts vary but little in this group 

 so far as as I have seen, and are not of value in determining 

 species ; the only difference is a slight variation in size in 

 different species. The mandibles are long, slightly curved, 

 bidentate and tipped with, or in some cases entirely, black ; 

 one of the teeth being somewhat longer. 



Behind, the head is somewhat hollowed out. 



The thorax is smooth or more or less distinctly punctate 

 and the thoracic sutures are often keeled or crenulate, espe- 

 cially between the pleurae. 



Prothorax (PI. I, figs. 1, 3). — The prothorax is divided 

 into two parts ; the slender collar which articulates above 

 with the head, and bears the anterior legs below, and be- 

 hind this on each side a triangular shaped piece extending 

 back to the insertion of the anterior wings. The collar fits 

 into a sort of socket in the front of the second part and meso- 

 thorax and is hardly visible from the side. Beneath, a weak 

 median groove runs from the articulation with the head to 

 between the insertion of the coxae, dividing the collar into 

 lateral lobes. 



Mesotkorax. — The mesonotum is a broad plate lying be- 

 tween the anterior wings, prothorax and the metathorax with 

 its edge frequently carinate. It is somewhat convex, usually 

 with more or less distinct parapsidal furrows running from 

 the anterior border to and converging on the posterior 

 border. They are sometimes distinct only in front, some- 

 times broad and crenulated or with one or more carinas, and 

 sometimes join at or before the posterior border. 



Behind the mesonotum but separated from it by a deep, 

 more or less distinct furrow lies the scutellum. Its center 

 is convex and circular or somewhat elongate, with more or 



TRANS. AM. ENT. SOC. , XXXVIII. 



