NO. 8 ANATOMICAL LIFE OF THE MOSQUITO SNODGRASS 



65 



across the back beneath the overhanging front end of the mesonotum, 

 and apparently a larger posterior plate on each side. This posterior 

 plate, however, tapers narrowly down to the coxa so that its lower part 

 must be epimeral. The episternum then is represented by a short plate 

 (Eps t ) between the first notal plate and the coxa. A plate in the side 

 of the neck (CvPl) that supports the head is unquestionably a cervical 

 sclerite. 



-AN 2 



n PNo 

 1 / ^ 



Fig. 25. — Thorax of Psorophora, with head and base of abdomen (from the 

 author's illustration in Howard, Dyar, and Knab, 1912). 



AN, wing-bearing notal plate ; CvPl, cervical plate ; Epm, epimeron ; Eps, 

 episternum ; eps, preepisternum ; Hit, halter ; N, notum ; PI, pleuron ; PIS, 

 pleural sulcus ; PN, postnotum ; pnf, paranotal fold ; S, sternum ; Scl, scutellum ; 

 Set, scutum; W, wing. 



Subnumbers 1,2,3 designate parts of prothorax, mesothorax, and metathorax. 



The metathorax is even more simplified than the prothorax. The 

 notum (fig. 25, N s ) is much narrowed across the back, but it expands 

 on the sides where it carries the halteres (Hit). From the notum the 

 pleural region continues downward on the side, tapering to the hind 

 coxa. Close to its posterior margin is a faint line that perhaps repre- 

 sents the pleural sulcus. A narrow strip (PN S ) between the meta- 

 notum and the first abdominal segment, more plainly seen in Aedes 

 (fig. 27 C,D, PN S ), is clearly the metapostnotum, since it gives at- 

 tachment to the first abdominal muscles (G). 



The wings of the mosquito have a simple pattern of venation, shown 

 at A of figure 26, in which the veins are named according to the Com- 



