2O ENTOMOLOGICAL NEWS [Jan., '14 



A lateral plate of the sternal region, the later osternite, Lst 

 (Fig. r) may become detached from the sternal region and 

 unite with the sclerite Lpl (Fig. i) to form a pre-coxal bridge 

 Lat (Fig. 3) extending in front of the coxa, and connecting 

 the pleural with the sternal region. This pre-coxal bridge 

 may then be divided by a suture b (Fig. 3) into an anterior 

 region, the precoxale, PCX (Fig. r) and a narrow posterior re- 

 gion, the antecoxale, or "antecoxal piece" of recent writers, 

 Acx (Figs. 3 and 6). The precoxal bridge, however, is usually 

 indistinguishably united with the episternum above, and with 

 the sternum below, in the higher insects. 



A secondary suture d (Figs. 2, 4, 5 and 6) marks off an 

 upper region, or anepisternum, Aes, in the dorsal region of the 

 pleural plate, and this small region is usually mistaken for the 

 episternum in such cases, although the episternum always ex- 

 tends from the top to the bottom of the pleural plate. Two 

 small "derivatives" of the region Aes, at the base of the wing, 

 may be more or less completely detached from this region to 

 form the anterior and posterior b as alar e, or basalar plates, 

 Aba and Pba (Figs. 2, 4, 5 and 6). 



The triangular plate termed the trochantin, Tn (Figs, i, 2 

 and 6) may possibly be a detached sclerite of the pleural plate, 

 although it is regarded by some writers as a detached portion 

 of the coxa. The trochantin may be divided by an oblique 

 suture into an anterior and posterior region as in Fig. 6 (Tn) ; 

 it may be divided into two distinct plates as in Fig. i (Tn) by 

 splitting up obliquely ; or it may split up transversely into two 

 distinct plates as in Fig. 3. The smaller of the two plates is 

 the trochantinelle, Tnl (Fig. 3). The dorsal portion of the 

 trochantin may unite with the pleural plate, and by a continua- 

 tion of the suture b (Fig. 2) a composite region, the pleuro- 

 trochantin, Ptn (Fig. 4) is formed. This is not to be con- 

 sidered as the trochantin alone, as is done by most writers. 



There occurs in some insects, a post-coxal sclerite, the post- 

 coxale, Poc (Fig. 2) which may unite with the lower portion 

 of the epimeron and with the sternite Fs to form a post-coxal 

 bridge Poc (Fig. 4) connecting the pleural with the sternal 

 region. There may thus be a pre-coxal and a post-coxal bridge 

 connecting the pleural and sternal regions. 



