PLATE XVI 



Figure 1. The thorax of Stomoxys calcitrant, hu., humerus. 

 psc"., the prescutum. sc., the scutum, scl., scutellum. 

 mtn"., metanotum. t'., tergite of the first abdominal 

 segment. a.s., anterior spiracle, ep'., episternum of 

 prothorax. eps"., episternum of mesothorax. ex'., 

 ex"., ex'"., coxae of the three pairs of legs, ms"., 

 mesosternum. epm"., epimeron of mesothorax. 

 mts'". , metasternum. eps'"., episternum of 

 metathorax. epm'"., epimeron of metathorax, or 

 lateral plate of the metasternum. p.s., posterior 

 spiracle. X 25 approx. 



Figure 2. The scales on the ptilinal membrane of Philaemato- 

 inyia insignis. X 1000 approx. 



Figure 3. The thoracic inlet of Stomoxys calcitrans, seen from 

 the inside, pn., pronotum. ap., apodeme. j., jugular 

 sclerite. cl., clavicle, ex'., coxa of the first leg. i.e., 

 interclavicle. a.s., anterior spiracle, hyt., hypotreme. 

 mb., membrane, pst., prosternum. x 60. 

 It should be noted, as a guide in dissection, 

 that the ventral margin of the inlet is much less rigid 

 than the dorsal. The prosternum can be bent on its 

 attachment. 



