The Life Processes of the Individual 



139 



is pulled and pushed through the maxillae. This motion 



action, bringing the liquid 



doubtless effects a pumpmg 

 through the temporary tube 

 formed by the curling of the 

 glossa. It is probably sucked 

 farther by the pharynx. The 

 glossa is also retracted into 

 the mentum and this with its 

 own contractility gives it great 

 flexibiUty of movement. 



Thorax. 



As explained earUer (p. 99), 

 the functional thorax of the 

 bee (Figs. 73 and 74) con- 

 sists of the three segments 

 which form the thorax in 

 other orders of insects and 

 the segment which is the first 

 abdominal segment of other 

 orders. This modification is 

 found in most other Hjrmen- 

 optera ' but the fact has seem- 

 ingly escaped most writers on 

 bees. The prothorax (1st 

 thoracic segment) is reduced 

 and the first pair of legs, 

 arising from this segment, are 

 loosely attached. The meso- 

 thorax (2d thoracic segment) 

 is specially well developed to 

 accommodate the large mus- 

 cles which propel the fore wings, while the metathorax (3d 

 thoracic segment) is reduced, consisting only of a narrow 

 plate (TS), the metatergum, and two lateral plates on 



Fig. 73. — Dorsal view of ventral 

 walls and internal skeleton of 

 worker. Much enlarged. 



' Snodgrass, R. E., 1909. Proc. U. S. Nat. Mus., XXXVI, pp. 511- 

 595. 



