1 34 Invertebrata. 



hereby many of them lay the vegetable kingdom 

 under great obligation, as they convey the pollen from 

 flower to flower and thereby fertilise the seeds of 

 many plants. Many bees secrete wax by means of a 

 wax gland placed in the abdomen, and with this 

 material they build their hexagonal cells for the shelter 

 of their eggs and larvae. 



The common humble bee makes a nest of moss; 

 others use clay or wood ; and some, like cuckoos, lay 

 their eggs in the nests of other species. 



In the hives of the common honey bee the inha- 

 bitants are of three kinds, the queen or perfect female, 

 the drones or males, and the workers or imperfect 

 females. 



Wasps have no special organ for the collection of 

 the pollen, and have their wings longitudinally folded; 

 they also have a more slender petiole or stalk joining 

 the abdomen and thorax. Many of these also live in 

 colonies, making nests of paper formed of vegetable 

 matter chewed by their jaws into a pulp and moulded 

 into hexagonal cells with rounded bases. Other 

 examples are the saw-flies which have a saw-like organ 

 for the deposition of their eggs, and the Ichneumons, 

 which have the singular instinct of laying their eggs in 

 the bodies of the larvae of other insects, so that the 

 young are hatched in the midst of abundant food, for 

 they feast upon the tissues of their host and barely 

 leave him enough of organ to prolong existence until 

 they are ready for emergence. 



Other Hymenopteious insects lay their eggs under 

 the cuticle of plants; and thereby form small tumours 

 or galls. One such species infests the oak and pro- 



