INTERRELATIONS OF INSECTS 277 



usually to be paralyzed, without being actually killed. The various 

 species of Sphecina frequently select particular species of insects or 

 spiders as food for the young. Pep sis formosa (Pompilidae) uses taran- 

 tulas for this purpose; Sphecius speciosus (Bembecidae) stores her nest 

 with a cicada; Nyssonidae pick out certain species of Membracidae; 

 mud-daubers (Sphecidae) use spiders; and other families of Sphecina 

 capture bees, beetles, plant lice or other insects, as the case may be. 

 he solitary wasps (Eumenidae) are similar to the digger wasps in habits. 

 . Of the solitary bees, Megachile is well known for its habit of cutting 

 ieces out of rose leaves; it uses oblong pieces to form a thimble-shaped 

 ube which, after being stored with pollen and nectar, is plugged with a 

 ircular piece of leaf. The larval cells are made either in tunnels ex- 

 avated in wood by the mother or else in cracks or other chance cavities. 

 One of the carpenter bees, Ceratina dupla, which builds in the hollow 

 tern of a plant a series of larval cells separated by partitions, is said by 

 omstock to watch over her nest until the young mature. 



The transition from the solitary to the social habit is indicated in the 

 ife-histories of wasps and bumblebees, where a solitary queen founds 

 colony but soon relegates to other individuals all duties except that 

 of egg-laying. The social insects will now be considered. 



i 



TERMITES 



Though popularly known as "white ants," the termites are quite 

 different from true ants, being indeed not very far removed from the 

 most primitive insects. In view of the extreme contrast in structure 

 and development between termites and ants, it is remarkable that the 

 two groups should have much the same kind of complex social 

 organization. 



Classes of Termites. In general, four principal kinds of adults are 

 produced in a community of termites, namely workers, soldiers, fertile 

 males and fertile females. 



The workers (Fig. 280, A) which are ordinarily the most numerous, 

 are of either sex, but their reproductive organs are undeveloped. A 

 worker ant or bee, is, however, always a female. The termite workers, 

 as the name implies, do most of the work; they make the nest, provide 

 food, feed and care for the young and the royal pair, and attend to 

 many other domestic duties. 



The soldiers, like the workers, are of either sex, with undeveloped 

 sexual organs. With monstrous mandibles and head (Fig. 280, B), 



