NO. 13 STAPHYLINIDAE BLACKWELDER QT] 



spiracle {sp. i) to form an articulation with the epimeron (pna). 

 The lateral anterior angles are extended along the antecostal suture to 

 the axillary region. Along the posterior part of the sclerite extends a 

 suture from the postnotal articulation to the midline, marking the 

 location of an interior ridge. This is the antecostal suture (acs). 

 There is no vestiture on the postnotum, but the narrow area caudad 

 of the antecostal suture is finely muricate. The central area is densely 

 covered with extremely minute rounded papilliform processes or 

 excrescences. 



The axillary sclerites will be described in the section dealing with the 

 wings. 



The ventral aspect of the metathorax is occupied by a single very 

 large sclerite, the metasternum (fig. 3 A, s.III). It extends from 

 the coxal cavities of the mesothorax to those of the metathorax, and 

 bears no sutures with the exception of a line from the anterolateral 

 angles around the coxal declivity. This line disappears medially and 

 is more of the nature of a fold, as it bears no internal expansions or 

 processes. The metasternum is separated from the mesosternum 

 (s. II) by a suture (ists) which disappears for a short distance on the 

 floor of the coxal cavity. Posteriorly the metasternum bears a small 

 triangular median emargination bounded by two rounded lobes, the 

 sternal articulations of the coxae (stca). Laterad of each articulation 

 is a broad shallow coxal emargination, and a slight expansion of the 

 sternum overlaps the coxal articulation with the pleuron. The entire 

 surface behind the line of the postcoxal folds is densely clothed with 

 long hairlike setae. The floor of the coxal cavity is finely strigulose 

 and nearly reticulate, and the area between the coxal depressions 

 and the poststernum is finely muricate. A narrow border of small setae 

 lines the posterior edge of the coxal depression on the anterior or 

 inner side of the coxal fold. 



The pleuron of the metathorax is divided longitudinally into the 

 usual two sclerites, the episternum, and the epimeron. The episternum 

 (figs. 3 A, 4G, cps.III) or the dorsal sclerite is very slender and 

 rather rectangular, and its posterior dorsal angle forms an articula- 

 tion for the lateral extremity of the metathoracic coxa. This articula- 

 tion is the pleural coxal articulation (cxla). With the exception of 

 a narrow band along the cephalic edge, the surface of the episternum 

 is densely clothed with long setae. Also the entire surface is strigu- 

 lose, the strigulae forming tiny folds over the base of each of the setae. 



The epimeron of the metathorax is larger than the episternum and 

 is secondarily marked with several longitudinal lines or sutures (fig. 

 4G). One of these sutures (cpms), marked by an internal ridge. 



