MONOBIA. 131 



This doubtless varies much. Its yellow markings are proba- 

 bly often more doveloped and the body partly encroached upon 

 by black. 



Hess, a. cliff. — This species is remarkable from its slender form 

 and its mctathorax puffed or chubby at the summit. By this 

 character it establishes itself in the genus Monobia and marks the 

 transition from the Montezumia. 



In its colors it recalls certain Odyneri of the old world (0. 

 multicolor and allies), and also certain Odyneri of its own country, 

 such as the 0. annulatus, pratensis, and in fine some Mexican 

 species, such as the 0. Iturbide. But it differs from all — 1st, 

 by its abdomen lengthened, not conical; 2d, by its metathorax 

 which is chubby at its summit on each side of the post-scutel, 

 because that is a little prolonged behind; 3d, by its labial palpi 

 distinctly composed of only three articles and the maxillary 

 clearly of five. 



It differs from the M. egregia by its metathorax, chubby at the 

 summit and truncate, not in a line with the post-scutel, but more 

 behind; having a smaller concavity and of another form, more 

 inclosed, and of which the spiniform angles are placed above the 

 middle. 



It approaches more to the M. variabilis in its form, but is 

 more slender, and the body is not strongly cribrose nor velvety, 

 as with this species, but smooth, satin-like, with glaucous reflec- 

 tions. 



Hab. Lower California. Taken at Cape St. Lucas by T. 

 Xantus. 



Observation. — With this species the buccal organs are but 

 little lengthened ; the tongue, the galea, and the maxillary palpi 

 are quite short ; the labial palpi are slender, the articles long. 



2. HI. cyanipennis Guer. 



Odynerus cyanipennis Guek. Voy. de la Coquille, Ins., 264; pi. ix, tig. 5, 



$(1830). 

 Monobia cyanipennis Sauss. Vospides, I, 96, 2. 



Ilab. Chili. (Typus in mus. Dom. Guerin Mencville.) 



