ADAPTATION OF ORGANISMS 325 



are sexually undeveloped females which do not lay eggs but 

 spend their time carrying water, collecting nectar and pollen, 

 secreting wax, building the comb, preparing food, tending 

 the young, and cleaning, airing, and defending the hive. 

 (Fig. 175.) 



The worker is a 'bundle of adaptations' for its varied 

 duties. Indeed, when we take away the adaptations there is 

 little left! The primitive insect appendages have become 

 specialized in the worker Bee so that collectively they con- 

 stitute a battery of tools adapted with great nicety to the 



MALK FEMALE WORKER 



FIG. 175. The Honey Bee, Apis mellifica. (After Shipley and MacBride.) 



uses for which they are employed. This applies to all of the 

 appendages of the insect's body, but we shall neglect those of 

 the head (Fig. 176) and consider only the specializations of 

 the three pairs of legs. These, as in all Insects, arise from 

 the THORAX; the anterior pair from the first segment of the 

 thorax (prothorax) ; the second, or middle, pair from the 

 second thoracic segment (mesothorax) ; and the posterior 

 pair from the third and last thoracic segment (metathorax). 

 A typical insect leg consists of several parts: the COXA, 

 which forms the junction with the body, followed in order by 

 the TROCHANTER, FEMUR, TIBIA, and five-jointed TARSUS, or 

 foot. (Fig. 177.) 



The worker Bee's PROTHORACIC LEGS show the following 

 specializations. The femur and tibia are covered with long, 



