288 ELEMENTARY ENTOMOLOGY 



b. TJic trochantcr. This is proportionally larger than in the 

 locust ; aside from this it shows no special modifications. 



c. The femur. This is a large, club-shaped joint covered with 

 long hairs. 



d. The tibia. This segment is smaller than the preceding and 

 is provided with a spine at the lower end. . 



e. TJie tarsus. The tarsus consists of five segments, the first 

 being nearly as large as the tibia. It is provided with a notch, near 

 its attachment to the tibia, which, together with the spine on the 

 latter segment, forms the antenna cleaner. 



Notice also the bilobed claws on the end of the tarsus, together 

 with the median, flaplike structure known as the empodium. This 

 secretes a sticky substance, which enables the bee to walk on a 

 smooth surface. 



Exercise 27. Make an enlarged drawing of a prothoracic leg, showing the 

 segmentation, antenna cleaner, claws, etc. 



3. Mesothoracic leg. The mesothoracic leg differs but slightly 

 from the prothoracic leg, except that the antenna cleaner is absent 

 and that on the inner side of the tibia there is a spur used in loosen- 

 ing the pollen from flowers. 



Exercise 28. Make drawing of the inner side of the tibia and tarsus of the 

 mesothoracic leg, showing the spine. 



4. Metathoracic leg. This resembles the prothoracic leg, with 

 the following modifications : 



a. The pollen-basket. The outer surface of the tibia of the third 

 thoracic leg is smooth and surrounded with a row of long, incurved 

 hairs. This is known as the pollen-basket, and is used in carrying 

 the pollen to the hive. 



b. The wax pincers. Between the end of the tibia and the tarsus 

 is a pincerlike structure consisting of a row of thick, flattened spines 

 on the edge of the tibia, which come in contact with the smooth 

 edge of the tarsus. These wax pincers are supposed to be used in re- 

 moving the plates of wax from the abdomen, where they are secreted. 



c. The pollen comb. This structure is located on the inner sur- 

 face of the flat, basal segment of the tarsus, and consists of nine 

 parallel rows of bristles, which are used in combing the pollen from 

 the body, where it collects while the bee is gathering nectar. 



