1G4 GEO. H. HORN, M. D. 



Tribe XXXIX.— Orthogonini. 



Antennse of variable length, more or less compressed beyond the third joint, 

 three basal joints glabrous, inserted under a slight frontal ridge, the condyle 

 however visible. Eyes moderately prominent, close to the mouth beneath. Head 

 short, oval, not constricted, front with two supra-orbital setse, clypeus moder- 

 ately prolonged, its front margin subcoriaceous, a setigerous puncture each side. 

 Labrum quadrangular, moderately prominent, apical margin sexsetose. Mandibles 

 slightly prominent, arcuate, acute at tip. MaxilliB usually hooked at tip, (except 

 Anoncopeucus), ciliate within and sometimes at tip, the outer lobe slender, palpi 

 moderate in length, last joint subcylindrical or ovate, apex obtuse. Mentum 

 emarginate without tooth, the emargination nearly filled with the basal membrane 

 of ligula, the latter moderately prominent, corneous, 2 — 6 setose at tip, the para- 

 glossse large, auriculate, and longer than the ligula, the palpi moderate, the last 

 two joints equal, the penultimate bisetose in front. Thorax broader than long, 

 lateral margin acute, depressed and without setigerous punctures. Elytra oblong 

 usually depressed, base margined, sides narrowly inflexed, margin entire, apex 

 usually truncate sometimes almost rounded, surface striate and with three dorsal 

 punctures, the first on the second interval near the third stria, the posterior two 

 near the second stria. Prosternum not prolonged. Mesosternal epimera narrow. 

 Metasternal epimera distinct, the posterior coxae contiguous. Legs moderately 

 stout, the tibise on the outer edge sulcate and carinulate, the carinae crenulate and 

 finely spinulose; anterior tibi« moderately stout, the outer apical angle acute, 

 inner side emarginate, tibial spurs moderate in length. Tarsi moderate in length, 

 the fourth joint emarginate or bilobed, the claws slender, simple or pectinate. 



The tarsi on all the feet are dilated in both sexes and are either densely pubes- 

 cent or densely papillose beneath. 



The only species of this tribe that I have been able to procure for 

 dissection is Orthogonius acrogonus Wied., in which I find the ligula 

 distinctly free at tip, the paragloss^ large and auriculate extending 

 beyond the ligula and united hehind the ligula by a thin translucent 

 membrane (108). 



It is interesting to find that in this tribe we have a genus with 

 the maxillae obtuse at tip, a character very irregularly diff'used in 

 the Carabida3. 



As indicated above the elytra are variable at tip, being either entire 

 or feebly truncate. Exceptional cases of this kind must be expected in 

 so extensive a family. 



In the present tribe the characters seem to indicate an aberrant 

 Truncatipenne with decided Harpalide affinities, Gh/ptus forming a link 

 in the line of affinity. As Zabrus seems to be the link between the 

 Fteroaticliini and Harpalini, so Orthogonius is between the Truncati- 

 penne complex and the Harpalini. 



An interesting essay on this tribe by Baron Chaudoir will be found 

 in the Annales de la Soe. Ent. Belg. xiv, pp. 95 — 130, in which will be 

 found an expression of opinion very nearly the same as that above. 



