66 



THE ANATOMY OF THE HONEY BEE, 



the general surface and mostly concealed between the niesothorax 

 and the juetalhorax. In hi^iier families such as the l^onipilida' the 

 j)ostnotuni of the mesotergum is entirely concealed by invaiiinaticn, 

 but it still carries a very large phra<i,ina. AVhen, now, we come to 

 the highest members of the order we find that the median part of the 

 postnotum in the niesothorax is gone entirely and that it is repre- 

 sented only by the lateral arms (figs. 2'2, PX ; 2P> A, PN.,) carrying 

 the large, purely internal postphragma (Pph). 



The mesopleurum is large iind consists principally of the episternum 

 (fig. 21, Eps.,)^ which, however, is continuously fused with the meso- 

 sternum (figs. 20 and 21, /S',). The pleural suture (fig. 21, P8.?i is 

 short and sinuous and does not reach more than half way from the 

 wing process to the base of the middle leg. The epimerum is reduced 

 to a small double plate lying above the episternum and posterior to 

 the wing process (figs. 21, Epm.^^ and 24 A, Eprn, and Epin). The 



pleural ridge (fig. 24 B, 7^^) 

 is weak, l)ut the wing process 

 {^VP) is well braced by a num- 

 ber of accessory internal ridges. 

 One preparapterum {'2P) and 

 one postparapterum {SP) are 

 present. Lying behind the 

 postparapterum is another 

 larger sclerite (fig. 24 A and 

 B, pn), Avhose anterior end is 



Fig. 22.— Lateral view of mesotergum of articulated to the edge of the 

 worker, removed from the rest cf thorax to . ^ . 



show large internal postscutellum (post- epimerUUl and whoSe pOSteFlOr 



notum, py) and its phragma {Pph) not taperiuo" end is looselv asso- 



visible normally in the bee from exterior. . - *^ . , . "' 



ciated with the terminal arms 

 of the postnotum (fig. 22, PX and pii). This sclerite might be 

 regarded as the fourth parai)teriim, l)ut it is much more probably 

 the representative of a small terminal bar of the postnotum present in 

 other Hymenoptera, such as PepsLs, which connects this tergal plate 

 W'ith the epimerum, though in this genus it is not detached from the 

 main postnotal sclerite. 



Both the mesosternum (fig. 20, /S.^) and the metasternum (*S'.,) con- 

 tribute to the formation of a large entosternum {Fi(.^+.^), which forms 

 a ]:)rotecting In'idge over the combined mesothoracic and metathoracic 

 ganglia (fig. 52) and affords attachment for the ventral longitudinal 

 muscles of the thorax (fig. 27, Imcl). 



The metathorax consists of a very narrow series of plates (fig. 21, 

 7^3, Pl^, and pl^) compressed between the niesothorax and the first 

 abdominal tergum {IT). Its back plate is a single, narrow, transverse 

 sclerite (figs. 21 and 2.'iA, T^) widening on the sides, where it carries 

 the wings by the two wing processes (fig. 23 A, ANP and PNP) . The 



