NO. 13 



STAPH YLINIDAE BLACK WELDER 



(>7 



of these may be found in any of the larger subfamiHes. It is obvious 

 that the shape of the pronotum cannot be used in the higher classifica- 

 tion. In certain groups it is useful in generic and specific segregation. 



The inflexed portion of the pronotum is generally closely united 

 with certain elements of the ventral surface and will be discussed in 

 the section dealing with the prosternal area. 



The ventral aspect of the prothorax affords a considerable amount 

 of variation in structure. The fundamental condition is frequently 



Fig. 21. — Intrafamily variation of the pronotum (continued from fig. 20). 



A, Metoponcus x'arians Slip. B, Cafius Hthocharinus Lee. C, Lorinota cingu- 

 lata (Lee.) ; D, Osorins nmndiis Shp. E, Liparocephalus brevipennis Makl. 

 F, Gcodroiniciis hrumwus (Say). G, Hypocyptus longicornis (Payk.). H, 

 ApJodcrus linearis Lee. 



obscured by the reduction of sclerites and the obliteration of sutures, 

 but several important characters are available. 



The amount of inflection of the pronotum varies somewhat, but 

 the size of the postcoxal lobe is more important and usable. These 

 lobes tend to close the coxal cavities behind, being almost successful 

 in Leptochints (fig. 22 F). In Lithocharis (fig. 22 B) and Xantholinus 

 (fig. 23 D) they are lacking entirely. 



The sternum varies greatly in length. The longest exposed area 

 occurs in Leptochints (fig. 22 F), but the large posterior lobe of 



