NO. 1687. TllU THORAX OF IMiBVTt^—iiNODOllAiiii, 557 



present paper. Xow, to liomolofj^ize the preepistermini of the Eii- 

 plexoptera (1)4. Pepi^) with this po.sterior subdivision (c/m) of the 

 Blattid episternum (32, 34, 35) requires too much anatomical contor- 

 tion, and the Avriter prefers to call the subsclerite in (juestion (^'/m) 

 simply a part of the episternum {Eps). Comstock and Kochi (IDO:')) 

 call it the '' second antecoxal piece," but it is unnecessary to give it 

 even this designation, which is also undesirable, because misleading. 



The trochantin of the Blattidte is likewise subdivided by an oblique 

 suture into a doi'sal part (35, 2'n) and a ventral part {fn). The 

 latter is identifiable as the trochantin by its coxal articulation (3*2, 35, 

 I'nC). Comstock and Kochi (1!)02) call it "the antecoxal piece." 

 Verhoeif (1903) recognizes it as the trochantin. 



In the Locustidtu (43, 44), the Gryllidie (47) and the Acridiidie 

 (57, 70, 71) the preepisternum {Peps) is separated from the epi- 

 sternum by a more or less distinct, though variable, suture. This 

 interpretation may appear doubtful, but a line is distinct in the 

 Acridiid nymph (55, 56) separating a large preepisternum (Peps) 

 from the episternum {Eps). In Aiufhi'us (43) the preepisternum 

 {Peps) falls in line with the presternal plate {Ps). 



A study of n^'uiphal forms (55) shows that the paraptera (/^), the 

 upper end of the pleural ridge {PP), and tlie wing process are de- 

 veloped only in connection with the adult wing. Short-winged 

 adults, however, such as Anahrus simplex (43, 44), have these parts 

 (P, ^VP) present, though somewhat rudimentary. 



4. Meso- and metanotum similar in most cases and often struc- 

 turally identical. 



In Blatella (38, 40) each is so simple in its construction that it 

 could be taken as a diagram of the generalized notal plan of structure. 

 (See text figs. 1 and 2.) Ventrally (40) it presents simple anterior 

 and 2)osterior marginal notal ridges {ANR^ PNP), the latter at the 

 front of a posterior reduplication {Pd), and a median V-shaped 

 ridge (F) or " entodorsum " of Amans (1885). These three ventral 

 ridges form lines on the surface (38, am', r, piw) marking off four 

 apparent notal subdivisions. The metanotum of a short-winged 

 female of Grijllns pennsijlraniciis is very similar (50) ; that of a long- 

 winged form differs in shape and has the anterior phragma {Aph) 

 highly developed, but is yet of the same fundamental generalized 

 type. In Mici'oeentuni the V-shaped ridge (F) is rudimentary in 

 both mesonotum (41) and metanotum (39), wdiile in the Mantid 

 adult (30) and nymph (31) its apex continues forward as two 

 parallel median ridges to the anterior marginal notal ridge. In 

 Acridiida^ (54) there is present an extra ventral ridge {ss) consisting 

 of two arms diverging outward and forward from the middle of the 

 IDOsterior notal ridge {PNR). The arms of this ridge {ss) cross 

 over the arms of the flattened and almost obsolete V ridge (F) . Their 



