in THORAX 103 



wing of a Hymenppteron. One of them becomes of considerable 

 size and importance in the Order just mentioned, and seems 

 to be articulated so as to exert pressure on the base of the 

 costa of the wing. This structure attains 

 its maximum of development in a genus 

 (? nondescript) of Scoliidae, as shown in Fig. 

 56. The best name for this sclerite seems 

 to be that proposed by Kirby and Spence, 

 tegula. Some writers call it paraptere, hypo- 

 ptt're, or squamule, and others have termed 

 it patagium ; this latter name is, however, 

 inadmissible, as it is applied to a process of 

 the prothorax we have already alluded to. F IG . 55 . _ Head and 

 To complete our account of the structure thorax of was P froni 



J . Bogota : t, tegula ; 0, 



of the thorax it is necessary to mention cer- base of wing. 

 tain hard parts projecting into its interior, 

 but of which there is usually little or no trace externally. A 

 large process in many Insects projects upwards from the sternum 

 in a forked manner. It was called by Audouin the entothorax ; 

 some modern authors prefer the term apophysis. Longitudinal 

 partitions of very large size, descending from the dorsum into 

 the interior, also exist ; these are called phragmas, and are of 

 a c great importance in some Insects with 



perfect flight, such as Hymenoptera, 

 Lepidoptera, and Diptera. There is no 

 phragma in connection with the prono- 

 tum, but behind this part there may 

 be three. A phragma has the appear- 

 ance of being a fold of the dorsum ; it 



FIG. 57. -Transverse section of SerV6S aS an attachment for muscles, 



skeleton of metathorax of and may probably be of service in 



SSS" S,S e l" <*er ways. More insignificant projec- 



metasteruum ; c, phragma ; tions into the interior are the little 



d, entothorax (apophysis or ,, , , /T -,. r K x 



furca) ; e, apodeme; /, ten- Pieces called apodemes (Fig. 5/, e); 



don of articulation. (After these are placed at the sides of the 



thorax near the wings. The apophyses 



are no doubt useful in preserving the delicate vital organs from 

 shocks, or from derangement by the muscular movements and 

 the changes of position of the body. 



The appendages of the thorax are () inferior, the legs ; (?>) 



