March, 1920.] NoTMAN : LeGS IX THE CaRABID.E. 81 



Strengthens the hold on the condyle but also serves as a fulcrum in 

 the motion of leg. The tooth on the intermediate cox?e is not so 

 strong not much more than a distinct angulation. 



While the anterior and intermediate coxae are condyles held by 

 the sternal plates; the posterior are plates, being immovable. The 

 upper surface, which is in the plane of the metasternum, corresponds 

 with the anterior surface of the other pairs; the apex and outer 

 cavity are perpendicular to the plane of the body, and the posterior 

 edge of both cavities is the suture between the coxae and the first 

 ventral segment. 



The upper surface, called the coxal plate, is triangular in form 

 with a rounded posterior apex, covering the base of the trochanter 

 and restricting the hind legs to a forward and back motion like that 

 in the swimming of a frog. The outer portion of the coxal plate 

 conjointly with the under plate forms a point extending to the outer 

 edge of the metasternum between the latter and the first ventral 

 segment. 



The coxal or upper plate is fiat and extends from the center or 

 near the center of the body to the outer edge of the metasternum. 

 It is widest near the inner edge and tapers rapidly to the outer ex- 

 tremity. In its simplest form as found in Dyschirins, Clivina and 

 Bembidhim, it has an acute edge throughout which is margined on 

 the outer half. It conceals entirely the vertical under plate when 

 viewed from above. In this form the coxae differ least from the 

 anterior and intermediate pairs. It is also found in Opisthius, 

 Leistus, PromecognatJiiis, the Pogonini, four species of Platynus — 

 larvalis, caudatus, disscctus and piisillus, in Lcptofrachelus, Casnonia 

 hidoviciana and Zacotus. 



In most species of Carabidae the upper plate is narrower exter- 

 nally and the under plate wider and oblique so that the latter is visible 

 from above. In Cychrus, Carahus, Calosoma, Galcrita, Cymindis, 

 Helluomorpha and Brachyniis the plates, which are of this type are 

 separated by an entire carina. In general, however, the carina is 

 lacking on the outer half of the coxae and the plates are separated 

 by a groove, the marginal groove of the upper plate. This groove 

 also is lacking on the outer fourth or third in Anomoglossus, Brachy- 

 lohus, and Lachuocrcpis. In the remaining genera, including the 

 three last named and a few species of Cychrus — hcros. clcratus. bi- 



