ODYNERUS. 219 



the 2d pair slightly bent in the first third, offering beneath in the 

 middle a dilation, lamellate, oblique, preceded by a wide notch 

 and channelled on its anterior face. 



Bess. a. diff. — This little species is very distinct in its numerous 

 characteristics. One cannot confound it with any Hypodynerus, 

 in view of its uniform black color and its infundibuliform first 

 abdominal segment, which does not offer an anterior and posterior 

 face, separated by a transverse ridge, etc. Its appearance is that 

 of Montezumia and of Nortonia. It is distinct from these genera 

 by the triangular form of the metathorax which recalls the form 

 of the thorax of Hypodynerus. The maxillary palpi are strongly 

 6-articulate, the 6th article being longer than the 5th; the labial 

 palpi have but three large articles; the 4th is very small, almost 

 rudimentary, which indicates a passage from Montezumia and 

 from Monobia. 



Hob. The elevated regions of the Republic of Ecuador. It 

 was taken by Dr. Maurice Wagner on the plateau of Tapia at 

 the foot of Chimborazo. (In collection of the author and collec- 

 tion of the Museum of Munich.) 



Observation. — The silvery hair of the clypeus is subject to fall 

 off, especially in the middle of this piece. The clypeus is often, 

 for this reason, only bordered with silver. 



II. First segment of the abdomen offering an anterior and a 

 superior face ; these two faces separated by a sort of trans- 

 verse ridge or swelling {the true Hypodynerus). 



A. Form much lengthened ; first abdominal segment small, nar- 

 row, nodiform or pedunculiform, very much narrower than 

 the 2d; its anterior face in a lengthened triangle. — Meta- 

 thorax with rounded angles; its excavation foiming a wide 

 vertical furrow. 



48. O. arciiatus Sadss. — Niger, velutinns, nigro-pilosus vel laevis, 

 punctulatus ; metanoto medio late canaliculato, polito; abdomine 

 depresso ; primo segmento trigonali, petiolato-cainpanulato, paene duplo 

 angustiore qnam secundum, supra transversim tnmido, apicis puncto 

 valde impresso ; secundo nee supra nee subtus tuberculato ; antennis 

 nigris, subtus basi ferrugineis; punctilio frontis luteo; pronoti et 

 abdominis segmentorum 1', 2' marline postico, albido ; tegulis pedi- 

 busque ferrugineis, bis basi uigris ; alis ferrugineis, apice fusco-cyaneis. 

 — Longit. 15 mm. 



