aETHOSYNUS. 179 



This species at first sight closely resembles Rhinotmetus by its 

 general character and bright blue colour. It may be distinguished, 

 however, not only by its more robust form, but by its transverse 

 (instead of elongated) thorax. It approaches more closely still to 

 Monoplatus, and might readily be taken for a large and robust female 

 of that group ; independently, however, of the structural peculiarities 

 of the mouth and tarsi, its thorax is not marked at the base by the 

 transverse thread-like line which obtains in every example of the 

 genus that I have been able to examine. Moreover I doubt whether 

 any true species of Monoplatus are found beyond the borders of the 

 provinces of Rio Janeiro, Sao Paulo, Minas Geraes, and Espiritu 

 Santo. 



Genus 31. GETHOSYNUS *. 



PALPI MAXILLARES dilatati, art. 3 incrassatissimo, ultimo brevi. 



PALPI LABIALES subcylindrici, elongati. 



ANTENTOE filiformes, sat robustce. 



CAPUT breve, depressum. 



THOKAX capite latior, transversus, lateribus subsinuatis. 



ELYTRA elongata, parallela, subcylindrica, haud ante medium trans- 

 verse depressa. 



PEDES robusti; tibiis posticis super tarsorum insertionem obsolete cal- 

 caratis. 



Labrum subcircular, contracted. 



Maxillary palpi (Tab. VII. fig. 6 m) dilated ; the basal joint small 

 and quadrate ; the second longer, dilated at the apex ; the third, in 

 length, not greater than, but, at the apex, double the breadth of, the 

 second ; the terminal joint minute. 



Labial palpi (Tab. VII. fig. 6 n) attenuated, subcylindrical, the 

 penultimate joint being slightly dilated near the apex. 



Antennas, approximate, situated immediately below the inner mar- 

 gin of the eyes, filiform, sufficiently robust ; the basal joint is con- 

 siderably dilated, more so than in the adjoining genera (approaching 

 in character the genus Physonychis) ; the third and fourth joints are 

 subequal, the fourth joint being slightly longer as well as more 

 attenuate than the third. 



Eyes globose, circular, lateral, situated near to the base of the 

 head. 



Head short, depressed, but not produced in front. 



Thorax distinctly broader than the head, transverse ; the anterior 



* yqOoavvos, lastus ; 



