SURROUNDINGS OF GROWING INSECTS 239 



discuss briefly the wide subject of the economy of social 

 insects from the view-point of the early stages in the life- 

 history. Interesting and noteworthy is the fact that the wasp, 

 bee, and ant grubs are tended and fed for the most part by 

 perfect insects which bear to them the relationship of older 

 maiden sisters. In the families of bumble-bees 1 and wasps 2 

 which last as communities only through one spring and summer 

 in our climate, the larvae from the first-laid eggs are cared for 

 by the queen, the later larvae mostly by the workers. The 

 wasp grubs lie in the hexagonal chambers of the comb, of 

 which successive layers are formed in the nest, the whole 

 structure being composed of paper worked-up out of wood- 

 fragments and spittle by the winged wasps, and receive their 

 food, consisting of insects caught and broken up, the nutritious 

 portions softened and masticated, by the workers. The 

 newly-emerged winged insects are stated to obtain from the 

 mouths of the grubs liquid food, consisting mostly of salivary 

 secretion ; later, when the larva is fully grown, this serves 

 as a silky covering for the mouth of the chamber, within 

 which the pupal stage is passed. The chambers in the under- 

 ground nests of bumble-bees (Bombus) are formed like the 

 honeycomb (Fig. 117) of the hive-bee (Apis) from wax 

 secreted by abdominal glands. These chambers are used for 

 egg-laying and the rearing of larvae, or for accumulating stores 

 of honey and pollen on which the larvae are fed. Each bumble- 

 bee larva, when fully grown, spins a silken cocoon and pupates, 

 the cocoons being aggregated in clusters. Within the nests, 

 both of wasps and bumble-bees, may be found larvae living as 

 inquilines, the eggs from which they were hatched having been 

 laid by females of related species. 



The communities of hive-bees and ants are, as is well known, 

 continuous from year to year, owing to the habit of storing 

 food for the support of the members through the winter. In 

 the hive-bee, the care and feeding of the larvae by the workers 

 reaches a high degree of specialization. The well-known 

 waxen honeycomb, with its approximately regular hexagonal 

 chambers, built by the worker-bees, is largely devoted to the 

 rearing of the grubs, an egg being laid by the queen-bee in 



1 F. W. L. Sladen : " The Humble-Bee ". London, 1912. 



2 C. Janet : " Observations sur les Guepes ". Paris, 1903. 



