CLASSIFICATION OF INSECTS. 385 



pollen in some subterranean mouse-nest or in a stump, and 

 the young hatching, gradually eat the pollen, and when it 

 is exhausted and they are fully fed, they spin an oval cylin- 

 drical cocoon ; the first brood are workers, the second males 

 and females. The partly hexagonal cells of the stingless 

 bees of the tropics {Melijjona) are built by the bees, while 

 the hexagonal cells of the honey-bee are made by the bees 

 from wax secreted by minute subcutaneous glands in the 

 abdomen. Though the cells are hexagonal, they are not 

 built with mathematical exactitude, the sides not always 

 being of the same length and thickness. 



The cells made for the young or larval drones are larger 

 than those of the workers, and the single queen cell is large 

 and irregularly slipper-shaped. Drone eggs are supposed by 

 Dzierzon and Siebold not to be fertilized, and that the queen 

 bee is the only animal which can produce either sex at will. 

 Certain worker-eggs have been known to transform into 

 queen bees. On the other hand, worker-bees may lay 

 drone eggs. The maximum longevity of a worker is eight 

 months, while some queens have been known to live five 

 years. The latter will often, under favorable circum- 

 stances, lay from 2000 to 3000 eggs a day. The first brood 

 of workers live about six weeks in summer, and are suc- 

 ceeded by a second brood. 



Class II.— INSECT A. 



A distinct head, thorax, and abdomen ; breathing by tracjiem ; wtually 

 with ametamorpJiosis. 



Sub-class I. Malacopoda. — Numerous simple spiracular openings ■with 

 isolated tracheal twigs ; nervous system with an incomplete 

 chain of minute ganglia, but the cords widely separated 

 (Peripatus), 



Sub-class II. Myriopoda. — Thorax and abdomen forming a continuous 

 region, with from six to two hundred joints, each bearing a 

 pair of genuine legs. 



Order 1. Ghilognaiha. — Body cylindrical or flattened, with no 

 sternum ; a distinct metamorphosis (Julus, Polydesmus). 



