298 PERIPATUS, MYRIOPODS, AND INSECTS. 



Sixteen ova, one from each ovarian tube, are usually 

 enclosed within each egg capsule. The latter is formed 

 from the secretion of the colleterial glands. Each egg is 

 enclosed in an oval shell, on which there are several little 

 holes (micropyles), through one of which a spermatozoon 

 enters. Spermatozoa, from the store within the spermatheca, 

 are included in the egg capsule. The development is 

 similar to that of other insects, and it has already been 

 mentioned that there is ho metamorphosis. 



At an early stage in development, some cells associated with the 

 mesoderm are set apart as reproductive cells, and originally these have 

 a segmental arrangement as in Annelids ; at a later stage other meso- 

 derm cells join these, some forming ova, others epithelial cells around the 

 latter. The distinction between truly reproductive cells and associated 

 epithelial cells, which is said to be late of appearing in some of the 

 higher insects, is established at a very early stage in the cockroach. 



Second Type of Insects. The BRITISH HIVE BEE 

 (Apis mellifica.) 



This is a much more highly specialised type than the 

 cockroach. It belongs to the order Hymenoptera. 



The Hive Bee (Apis mellifica) is a native of this country, 

 and is the species most commonly found domesticated. It 

 is the only British representative of the genus Apis, and 

 exhibits, in its most fully developed form, the social life 

 which is foreshadowed among the Humble Bees. As a 

 consequence of this social life, there is much division of 

 labour, which expresses itself alike in habit and in structure. 

 The males (drones) take no part in the work of the colony, 

 and have solely a reproductive function ; the females are 

 divided into two groups the queen bees and the workers. 

 In the workers, which do, in fact, perform all the work of 

 the hive, the vegetative organs attain their highest degree 

 of development, but the reproductive organs are normally 

 abortive and functionless. In the queens, of which there is 

 but one adult to each hive, the enormous development of 

 the reproductive organs seems to act as a check upon the 

 vegetative organs, which are of less advanced type than 

 those of the workers. The workers are further divisible into 

 nurses, which are young and do not leave the hive, being 



