PHYLUM ARTHROPOD A 



3*7 



the hind wing, which are inserted into a trough-like fold in the 

 posterior margin of the fore wing. When flying, the wings act 

 as inclined planes, 

 and locomotion for- 

 ward is attained by 

 both up and down 

 strokes, the tips of 

 the wings moving in 

 a curve shaped like 

 a figure S. Motion 

 backward, or a sud- 

 den stop, may be 

 accomplished by 

 changing the inclina- 

 tion of the plane of 

 oscillation. 



The abdomen is 

 made up of a series 

 of six visible seg- 

 ments; thin, chitin- 

 ous membranes con- 

 nect the segments 

 and make the move- 

 ment and expansion 

 of the abdomen pos- 

 sible. Each of the 

 last four visible seg- 

 ments of the worker 



FIG. 240. Sting of worker honey-bee, b, barbs 

 bears a pair of Wax on darts; /. k, I, levers to move darts; n, nerves; 



elands At the end of p ' stin ^- fep| >r : #S, poison gland; ps, poison sac; 



sh, sheath; jth g, fifth abdominal ganglion. (From 

 the abdomen of the Packard, after Cheshire.) 



worker and queen is 



the sting, and the slit-like openings of the sexual organs and anus. 



There is no sting in the drone, but a copnhitory organ is present. 



The sting is a very complicated structure (Fig. 240). Before 



