NO. 2 



HONEY BEE SNODGRASS 



41 



part of the wing bases on its sides. In a study of the mechanism of 

 the thorax rather than its morphology, however, it will be better to 

 follow the mechanical pattern of the structure, in which the meso- 

 notum consists of an anterior notal plate and a posterior notal plate. 

 The reason for the division of the notum into these two plates will 

 be clear when we study the wing mechanism. 



Fig. 15. — The thorax and the base of the abdomen (drone), left side, wings 

 removed. 



e, occipital process of proepisternum ; Epm, epimeron of mesopleuron ; Epsi, 

 prothoracic episternum ; EpSi, mesothoracic episternum ; i, groove between 

 mesopleuron and metapleuron ; IIS, sternum of first abdominal segment ; IIT, 

 HIT, tergal plates of first and second abdominal segments ; IT, tergal plate of 

 propodeum ; /, groove between metanotum and propodeum ; Li, Li, Lz, legs ; 

 m, n, groove between metapleuron and propodeum ; Ni, pronotum ; N2, meso- 

 notum ; N3, metanotum ; yis, primary notal sulcus between scutum and scutellum ; 

 Ph, pU, upper and lower parts of metapleuron ; pls2, pleural sulcus of meso- 

 thorax ; 6*2, mesosternum ; Ss, metasternum ; ScU, scutellum of mesonotum ; 

 Sctz, scutum of mesonotum ; set, posterolateral subdivision of mesoscutum ; 

 sf, scutal fissure ; spl, spiracular lobe of pronotum ; Tg, tegula. 



The anterior mesonotal plate (figs. 15, 16 C, Set) is a large, shield- 

 shaped sclerite (fig. 16 B) convex dorsally and strongly declivous 

 anteriorly. Its front margin is deflected into the relatively small 

 prephragma (iPh), and on its lateral margins are the anterior notal 

 wing processes (ANP). The posterior, scutoscutellar mesonotal 

 plate (figs. 15, 16 C, Scl, set) is somewhat crescent-shaped as seen 

 from above (fig. 16 A) or below (D) with the concave margin 

 anterior ; internally it is braced by the strong scutoscutellar notal 

 ridge (D, NR). The lateral scutal areas of the plate bear the 

 posterior notal wing processes, and the tapering ends of the scutellar 



