NO. 2242. MORPHOLOGY OF THE STREPSIPTERA— PIERCE. 415 



stand. The scutellum is only connected distinctly by the cord to the 

 tiny area far behind on epimeron opposite the base of the scutellum. 



The wing venation typically consists of eight radial veins, costa, 

 subcosta, radius, medius, cubitus, and three anal. The costa is but 

 a short humeral thickening, beside the subcosta, which arises from 

 it and braces the anterior margin to the middle of the Aving. In 

 Triozocera (pi. 64, fig, 2) the radius and medius do not have basal 

 connections, but appear to arise from subcosta. Cubitus is isolated. 

 The first and second anal arise from a strong basal area, and the 

 third anal is represented by a darkened area only. In this genus a 

 detached piece of radius strengthens the border beyond the apex of 

 subcosta. Medius has beyond the middle two detached branches, 

 one in front and one behind. 



In Pyrillo'xenos the number of veins is as above with the exception 

 of the second medial branch and the third anal, both of which are 

 lacking. Here radius branches from medius, and these with cubitus 

 have a common source (pi. 77, fig. 7). 



The cubital and anal veins are less stable than the others, and in 

 the Elenchidae only one of them persists. The number of detached 

 branches of radius and medius is also variable and has been dis- 

 cussed in previous contributions of the writer. 



Pleural suture. — This suture between the episternum and epimeron 

 is diagonally longitudinal from the base of the wing to the coxa, as 

 in Diozocera insularum (Diozoceridae) (pi. 78, fig. 7), and Tetro- 

 zocera santchii (Mengenillidae) (pi. 66, fig. 3). It is often ter- 

 minated on the sternum opposite the junction of eusternum and 

 sternellum, as in Xenos (pi. 72, fig. 1). 



Epimeron. — The epimeron is usually a very narrow elongate piece, 

 reaching the base of the wing in a point and extending back above 

 the pleural suture and beyond it to the coxa. It is sometimes sepa- 

 rated into several parts. In Tetrozocera it is one continuous un- 

 broken area from wing to coxa and hardly varies in width (pi. 66, 

 fig. 3). In Triozocera it is interrupted by the small detached scu- 

 tellar piece to which the axillary cord is attached (pi. 65, fig. 6). 

 A similar piece of scutellum with attachment to the axillary cord 

 occurs on the epimeral area of Neostylops crawfordi and Xenos ves- 

 parum. We may consider the part of epimeron in front of this little 

 piece the epimeron pteropleurite and the posterior part which reaches 

 the base of the coxae as hypoepimeron (pi. 65, fig. 6; pi. 66, fig, 7; 

 pi. 70, fig. 4; pL 72, fig. 1). 



In many species epimeron also shows relationship to the sternellum 

 (fureasternite of Crampton), This is in case the pleural suture does 

 not reach the coxa, as in Triozocera (pi. 65, fig. 7), Xenos (pi. 72, fig, 

 1), and Delphacixenos (pi. 75, fig. 2), in which case epimeron and 

 sternellum are fused. 



