CONSIDERATIONS. 477 



between its two divisions the external branch of the aUferous 

 apophysis. Besides this direct articulation, each elytron 

 articulates indirectly with the " ecusson " and first ilium by 

 four small moveable pieces; one {preepauliere), placed in 

 front of the bifurcate apophysis of the elytra ; the others, 

 {epauUeres anterieure, moyenne, et posterieure), placed 

 behind the same apophysis. Their situation and structure 

 can only be learned by a very careful examination of the 

 animal itself. 



The mctathorax is formed of eighteen parts, ten of which 

 have their analogues in the mesotJiorax, Its under surface is 

 occupied by a sternum resembling that of the mesothorax, but 

 double its size ; its wings are rhomboidal, and extend from the 

 mesothorax to the coxcb of the last pair of legs {tnetapedes, 

 Newman), to which they are united by a squamose articulation. 

 The lateral angle of these wings presents a small apophysis, 

 on which are articulated, on one hand, the coxce of the meta- 

 pedes, and, on the other, the second ischium. On the medial 

 line of the sternum {inetasternuvi of authors) rises a stout verti- 

 cal plate, terminated by three long apophyses, one directed 

 forward, the other obliquely, outward and upward. The ver- 

 tical plate is the posterior episternal apophyses ; the branches 

 are its anterior and lateral cornua. 



On each side of the mesothorax are two parts analogous to 

 the ilia, but differently formed; these are the ischia, or 

 pieces ischiatiques. The second ischium is a flat semi-oval 

 plate, placed above the wing of the metasternum, occupying its 

 whole width, and united to it by a squamose articulation. Its 

 upper margin is united to the first ischium, which is of a very 

 irregular form, presenting behind a quadrangular external part 

 placed on a level with the second ischium; to which it is 

 united by its inferior margin ; posteriorly, it borders upon the 

 hinder coxa ; above, it partly covers the membranous band of 

 the first segment of the abdomen, (^propodeon, Newman) ; its 

 anterior part is united to the piece costale. Its antero-inferior 

 angle is prolonged into a narrow band, bounding the upper 

 margin of the second ischium for about two-thirds of its length, 

 when it rises, and forms a long apophysis, {alifere posferieure,) 

 directed upwards, forward, and inwards, serving to support the 

 wing. 



The costal {piece costale) is an almost membranous plate, 



