Chap. 30 ARTHROPODS INSECTS, SPIDERS, AND ALLIES 617 



Sting. The sting of a bee is an ovipositor modified into a weapon. Its ex- 

 ternal parts are two feelers that locate the point to be stung, and a needle, 

 composed of two barbed shafts that slide within a shaft. Connected with this 

 is the internal poison sac that receives the poison from adjoining glands. Bees 

 sting to defend the colony; thus stinging is a social act. It often kills the bee 

 because the shafts catch in the flesh and the whole stinging mechanism is 

 pulled out of the bee. 



Digestive System. The special feature of the digestive system is the honey 

 stomach, a modified crop used as a tank to carry nectar from the flowers to 

 the honey cells in the comb (Fig. 30.23). A short tube (proventriculus) con- 

 taining a valve connects the honey stomach with the true stomach (ventric- 

 ulus). The valve is closed except when the bee takes some of the nectar for 

 itself but what signals the opening of the valve is not known. The honey 

 stomach is very distensible and when full of nectar, looks hke a transparent 

 balloon. Honeybees fly rapidly, distances of a mile or more, or make short 

 trips — ones with quick stops and starts from flower to flower. The supply of 

 oxygen in the air-sacs probably eases up on breathing during flight (Fig. 

 30.24). 



Nervous System — Coordination. As might be expected from their be- 

 havior, ants, wasps, and bees have the most highly developed nervous systems 

 of any insects. In the bees the ventral nerve chain is characteristically shorter 

 and more ganglia are fused than in the grasshopper (Fig. 30.18). 



The Senses and Language of Honeybees. The statements that follow give 



Phorynx 



Pottcerebrai 

 glands 



Honey 

 •tomoch 



Molpighion 

 tubules 



Rectum 



Phoryngeal 

 glands 



Esophag us 



Salivary 

 glands 



Honey 

 stopper 



Ventriculus 



Small 

 intestine 



Rectal gland 



Fig. 30.23. The digestive system of the worker honeybee. (Courtesy, Hunter and 

 Hunter: College Zoology. Philadelphia, W. B Saunders Co., 1949.) 



