100 ENTOMOLOGICAL SOCIETY 



with the wing and bearing the insertion of the pronator wing 

 muscles on their inner surfaces. These plates (iP and 2P) 

 are usually termed the paraptera {pteropleure of Verhoeff), 

 and their modifications in different orders is of special im- 

 portance. In most of the lower insects there are two for each 

 pleurum and they can be seen best in Acridiidse where they 

 are situated one before the other just in front of the wing 

 process ( WP). In the mesothorax and metathorax of Mantidae 

 (figs. 2 and 4) the pleurum is horizontal, and consequently 

 the paraptera (iP and 2P) lie below the wing process {WP). 

 The ventral one is much larger than the other and has a small 

 neck at its anterior angle. In Spongophora (figs. 11 and 12) 

 the metapleurum is similar in position to that of the mantid. 

 The first, or here ventral, parapterum (iP) is, however, pro- 

 portionately larger and is partially fused with the episternum. 

 Its anterior end is produced into a slender arm parallel with the 

 wing process {IV P) and its lower edge is extended by a thin 

 plate forming a circular disc internally (fig. 11, MD) for the 

 pronator muscles of the wing. If we compare this structure 

 now with the metapleurum of a cerambycid (figs. 20 and 22) 

 the resemblance is certainly striking. The only difference is 

 that the second parapterum is lacking and the first is more 

 completely fused with the episternum. Any phylogenetic con- 

 siderations based on this similarity of structure are invalidated, 

 however, by the fact that in the lower beetles such as the 

 Carabidse and Dytiscidse the parapterum is only articulated to 

 the episternum and the resemblance to Euplexoptera is much 

 less than in the higher beetles (compare figs. 26 and 27 with 

 figs. II and 12, and figs. 20 and 22 with figs. 11 and 12). In 

 the mesothorax of Coleoptera the parapterum is usually re- 

 duced to a small and very inconspicuous plate or bar lying near 

 the wing process (figs. 16 and 17, P), but in Cyllene rohinicB 

 (Cerambycidse) it is prominent and bears a large disc (fig. 

 23, P)- 



THE ORTHOPTERA. 



The illustrations in this order are taken principally from 

 the Blattidse and the Mantidae. These two groups probably 

 present more primitive characters than any of the other Or- 

 thoptera, but none of the orthopteran families are related 

 serially to one another. 



TJic microthorax of Spodroniantis guttata is shown in fig. 

 I. The submentum {Sm) is here clearly articulated to the 

 microthoracic sclerites by its basal angles. There are two 

 sternal plates present and a pleural series of four plates on 

 each side. The notum consists of two narrow median plates. 



