ADAPTATION OF ORGANISMS 329 



SPUR, which is employed in removing the pollen from the 

 pollen baskets on the metathoracic legs, and also in cleaning 

 the wings. 



The METATHORACIC LEGS exhibit four remarkable adapta- 

 tions to the needs of the insect known as the POLLEN COMBS, 

 PECTEN, AURICLE, and POLLEN BASKET. The pollen combs 

 comprise a series of rows of bristle-like hairs on the inner sur- 

 face of the first segment of the tarsus: the pecten is a series 

 of spines on the distal end of the tibia which is opposed by a 

 concavity, the auricle, on the proximal end of the tarsal seg- 

 ment; while the pollen basket is formed by a depression on 

 the outer surface of the tibia which is arched over by rows of 

 long curved bristles arising from its edges. 



Thus the worker is fully equipped. Flying from flower to 

 flower for nectar, the Bee brushes against the anthers laden 

 with pollen, some of which adheres to the hairs on its body 

 and legs. While still in the field, the pollen combs are first 

 brought into play to comb the pollen from the hairs, while 

 the pectens scrape the pollen from the combs. Then the 

 auricles are manipulated so that the accumulating mass of 

 pollen is pushed up into the bristle-covered pollen baskets. 

 This process is repeated until the baskets are full and then 

 the insect returns to the hive, where the contents of the pollen 

 baskets are removed by the aid of the spurs with which the 

 mesothoracic legs are provided. 



Moreover, the structural adaptations of the worker Bee 

 are but one aspect of a reciprocal fitness. Many of the 

 flowers which the Bee visits show remarkable adaptations 

 for the reception of the Bee and for dusting it with 

 pollen, because Bees are effective agents in transfer- 

 ring pollen from flower to flower and thus insuring cross- 

 fertilization. 



