1909.] NATURAL SCIENCES OF PHILADELPHIA. 27 



If one compare the mesothoracic trochantin of a Blattid (pi. Ill) 

 with that of Chrysopa (fig. 3) and Corydalis (fig. 17), it appears that the 

 so-called trochantin of Chrysopa and Corydalis correspond only to the 

 "minor" region in the cockroach. The condition in Corydalis indi- 

 cates that the minor region may become constricted off and form what 

 is usually considered the entire trochantin in certain insects, while 

 the major region fuses with the episternum — as it partially does in the 

 pro thorax of the Blattidse. 



In the cockroach this breaking of the prothoracic trochantin into 

 two pieces is so evident that it is difficult to see how Sharp, '95, could 

 have so confused these sclerites in his figure of 

 Blabera gigantea {Cambridge Natural History, 

 Vol. I, p. 222). He has turned the figure upside 

 down, thus making it more difficult to see what he 

 is trying to show, but it is quite plain that the 

 portion he terms the entire trochantin is only the 

 minor region, while his " epimeron( ?) " is the Fig. 13. — Lyda. — 

 major region of the trochantin. The true epimeron ^oCTviSS^and 

 is the sclerite he designates as a fold of the pro- prothorax. 

 notum. 



In the mesothorax of Forficula (pi. II) the trochantin is not trans- 

 versely, but longitudinally divided into separate pieces (T & and T^). 

 In the Blattidse (fig. 21 and pi. Ill) this division is indicated by a longi- 

 tudinal suture — the trochantinal suture — which is present not only in 

 the meso- and meta-thoracic trochantin {T" and T'"), but also in the 

 major and minor portions of the prothoracic trochantin (T\ and T' 2 ), 

 thus clearly indicating that the latter are but parts of a single piece. 

 Of the two regions marked off by the trochantinal suture, the posterior 

 one will be termed the coxal trochantin 10 (pi. Ill, T^) and the anterior 

 region will be referred to as the antecoxal trochantin (T a ). 



Comstock, '02, terms the antecoxal trochantin (TV) the antecoxal 

 piece, and refers to the antecoxal laterale (T h ) as the second antecoxal 

 piece. In using the terms antecoxal trochantin and antecoxal laterale 

 an attempt has been here made to retain Comstock's terms, and yet 

 make it clear to what region the parts so designated belong. It must 

 be borne in mind that Comstock's, '02, antecoxal piece (i.e., the ante- 

 coxal trochantin) is not the same as Walton's, '00, antecoxal piece 

 (the antecoxal laterale), and neither of these sclerites corresponds to 



10 With reference to the designation of this sclerite, the term "accessory tro- 

 chantin plate" (Snodgrass, '08), of which the writer was not aware at the time 

 the above given terminology was proposed, has the right of priority. 



