NO. 2 



HONEY BEE — SNODGRASS 



47 



The second spiracles lie below the wings in the membrane concealed 

 between the upper edges of the mesothoracic and metathoracic pleura. 

 They are minute apertures without a closing apparatus, and have been 



Fig. 17. — The mesopleuron and the first spiracle (drone). 



A, left mesopleuron, lateral view. B, right mesopleuron, mesal view. C, right 

 first spiracle and adjoining parts of prothorax and mesothorax, mesal view. 

 D, right spiracular lobe of pronotum, mesal view. E, mesopleural muscles 

 arising on episternum, right side, mesal view. F, right first spiracle and con- 

 nected trachea, mesal view. G, posterior pleural muscles of mesothorax, right 

 side, mesal view. 



a, platelike thickening of intersegmental membrane connecting spiracle lobe 

 of pronotum with mesepisternum ; b, lobe of mesepisternum supporting a: 

 c, depression of mesepisternum covered by spiracular lobe of pronotum ; d, lobe 

 of mesepisternum supporting basalare ; e, recurrent groove of mesopleuron ; 

 /, internal ridge of recurrent groove ; g, mesal inflection of mesopleuron con- 

 tinuous with pleural ridge (PIR) ; h. epimeral plate supporting subalare ; ;, point 

 at which mesoscutum is supported on pleuron. 



observed by the writer only in the worker. The third spiracles are 

 those of the propodeum, and have the structure of the other ab- 

 dominal spiracles. Each is provided with a short occlusor muscle 

 (fig. 27 B, 12^) stretched between the two ends of the spiracle, and 



4 



