16 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



of the elytra; unlike the mesothoracic stigma it is surrounded b,y the 

 soft cuticle; it is large and deeply impressed and the rima stigmatis 

 is antero-posteriorly directed; that of the mesothoracic stigma is di- 

 rected antero-internall3^ 



The dorsum of the mesothorax is more or less chitinized laterally, 

 less so at middle behind the scutellum. Invisible without removal 

 of the eh^tra. 



The dorsum of the metathorax is membranous except laterally 

 where the episternum extends inward for a short distance beneath 

 the epipleura. 



The pvoacetdbula are quite circular, except at the internal margin 

 where the intercoxal prosternal process dilates slightly and impinges 

 upon them. 



The mesacetahnla are quite circular if the recess for the trochan- 

 tine be not included, with that it is slightly transverse. The anterior 

 margin of the acetabular recess is more or less angulate from the 

 truncate externo-posterior angle of the mesosternum ; the posterior 

 margin is continuousl}^ arcuate with that of the acetabulum proper. 



The metacetaljvla are slightly more transverse, but slightly and 

 obtusely angulate anteriorly where the posterior angles of the meta- 

 sternal alse form their boundarA^ 



The procoxa are globose. 



The niesocoxcB are really slightly transverse, but subdivided by an 

 antero-posterior impression into the rounded coxa proper and the 

 outer and smaller division, — the trochantine which occupies the ace- 

 tabular recess. The coxa proper is quite broadly and outwardly im- 

 pressed from the articular cavity to the trochantine. 



The ■metacoxii' are more transverse, ovate and not divided by an 

 antero-posterior impression ; the surface of each is broadly and 

 strongly grooved external to the articular cavity. 



The froelianfers are small and ovate, scarcely forming a half of the 

 width of the basal extremity of a femur, and but a little longer than 

 wide. 



The criirdl clutrdcters are given under the ditlerent specific head- 

 ings. YoY a study of the relative lengths of tli(> di tie rent segments 

 see diagram, fig. 4, Plate 8. 



The grooxes on the inferior surfaces of the femora I have denomi- 

 nated as the t'llncd, grooves; because they are adapted to and receive 

 the tibia3 in extreme flexion. 



Likewise the grooves observed on the external surfaces of the 

 tibia^ I call the tarsal grooves. These tarsal grooves are not always 

 present in the different species; when present they extend from the 

 more or less open articular cavities on the tibial apices, to become 

 evanescent at varying distances from the same. These tarsal grooves 

 receive the tarsi in hyperextension. 



