22 ENTOMOLOGICAL NEWS [Jan., '14 



while their distal extremities remain separated to form the 

 arms of the fork. 



Following the furcasternite is the p o st f ur cast emit e, Pfs 

 (Figs. 2 and 5), and behind this is the spinasternite, Ss (Figs. 



1, 2, 3, 4, 5 and 6), so called because it bears the spina, or 

 unpaired median apophysis (monapophysis) . It has not yet been 

 determined whether or not the spinasternite is the foremost or 

 the hindmost of the sternites, but it is here treated as though 

 it were the hindmost. 



The internal projections of the sternal region are 

 termed a\pophyses. In order to distinguish the paired 

 from the unpaired apophyses, the terms diapophyses and 

 moncapophysis may be used to designate the two types. 



A median ventral fold, the mid-ventral "implex," with its 

 corresponding external suture, frequently partly divides the 

 sternal sclerites into symmetrical halves. It, however, is absent 

 in many insects. 



All of the sternites mentioned above are not preserved in the 

 higher insects, the two usually represented being the basister- 

 nite and the furcasternite (called the antecoxal piece by the 

 older writers). The prebasisternite is retained in the pro- 

 thorax of certain lower forms, and two derivatives, or detached 

 portions, of this region occur as narrow transverse plates, the 

 int erst emit es, Is (Figs. 2 and 3), in the prosternum of the ear- 

 wig and roach. 



INTERSEGMENTALIA The term intersegmewtat plates, or 

 intersegmentalia is applied to the small sclerites situated be- 

 tween the segments. These plates, in all probability, belong 

 partly to the segment in front of them, partly to the segment 

 behind them, and are therefore not to be considered as vestiges 

 of reduced segments in the process of becoming lost. 



The dorsal intersegmentals are the intertergites, It (Figs. 



2, 3 and 4). They occur in front of the mesonotum of Cory- 

 dolls (Fig. 4, It) and in front of the pronotum of the roach 

 (Fig. 3, It). Those in front of the pronotum are called the 

 dorsal cervicals (cervicalia). The dorsal intersegmentals are 

 probably detached plates belonging to the segment in front of 

 them. 



