1909.] NATURAL SCIENCES OF PHILADELPHIA. 25 



cockroach), but transversely, i.e., along the line / e (fig. 20), we would 

 have the condition found in the earwig (see fig. 19, compare also pi. 

 II). The region nearest the episternum (ES) may be termed the 

 episternal laterale (Lj), and that next the sternum (S) the sternal 

 laterale (L 2 ). In Forficula there is a third piece, the "hyposternal 

 laterale" (L 3 ), which is not so deeply pigmented as the other two. It 

 is usually covered by the sternum, and in Anisolabis it appears to be 

 fused with the sternal laterale. 



The interpretation of the relations of these sclerites as given by 

 Verhoeff, '03, differs very widely from the one just discussed. This 

 investigator homologizes the episternum of the earwig (fig. 19, ES) 

 with the episternum plus the anterior laterale in the cockroach (fig. 

 21, ES + La). The earwig's episternal laterale (fig. 19, L x ) he homo- 

 logizes with the antecoxal laterale of the cockroach (fig. 21, L\>); and 

 as the earwig's sternal laterale (fig. 19, L 2 ) would then have no corre- 

 sponding sclerite in the cockroach, Verhoeff seeks to explain the sternal 

 laterale as a "Vorplatte" or anterior plate which lies in front of the 

 sternum in the pro thorax (i.e., a lateral cervical?), but in the meso- 

 and metathorax it is supposed in some way to become drawn around 

 to the side of the sternum and take up a position between the latter 

 and the antecoxal laterale (or "katopleure"). The musculature gives 

 no indication of such a caudad migration of the lateral cervicals, or 

 of any other " Vorderstuck," and it is difficult to see how such a theory 

 can be supported. On the other hand, it is quite comprehensible that 

 a transverse, as well as a longitudinal division might occur, since a 

 similar division is clearly traceable in the prothoracic trochantin of 

 the Blattidse. 



In the metathorax of the Dermaptera (or Euplexoptera) the sterna) 



laterale has apparently fused with the sternum (pi. II). In the 



prothorax of Anisolabis (pi. II) the 



episternal laterale (L t ) has partially 



fused with the episternum, but traces 



of its outlines are still preserved. The 



sternal laterale may be readily observed 



as a distinct sclerite (L 2 ), but both it 



and the episternal laterale (L 2 ) are 



,, .... —,. , Fig. 12. — Pterostichus. — Dor- 



greatly reduced m size. The protho- sal view of the me tathorax, 



racic sternal laterale (L,) is entirely showing the sternellum (N"\) 

 , . ,. r ,, • i i -x partially covered by two flaps 



distinct from the cervical sclerites of the parapsidoscutum. 



(C*S 2X ), which lie in a plane below it; 



yet Borner, '03, confuses it with the cervicals, and homologizes it 



