INTERRELATIONS OF INSECTS 315 



ously a ball of dung 1 which is to serve as larval food. The 

 female mole-cricket (Gryllotalpa) is said to care for her eggs 

 and even to feed the young at first. 



Hymenoptera display all degrees of complexity in regard to 

 maternal provision. Tenthredinidse simply lay their eggs on 

 the proper food plants or else insert them into the tissues of 

 the plants. Sphecina make a nest, provision it with food and 

 leave the young to care for themselves. Queen wasps and 

 bumble bees go a step further in feeding the first larvae and 

 carrying them to maturity. Finally, in the honey bee the care 

 of the young is at once relegated by the queen to other individ- 

 uals of the colony, as is also the case among ants. 



Some of the most elaborate examples of purely maternal 

 provision are found among the digger wasps and the solitary 

 wasps; these instances are highly interesting, involving as they 

 do an intricate co-ordination of many reflex actions as ap- 

 pears in the discussion of insect behavior. 



Among the Sphecina, or digger wasps, the female makes a 

 nest by burrowing into the ground, by mining into such pithy 

 plants as elder or sumach, or else by plastering bits of mud 

 together. The nest is provisioned with insects or spiders 

 which have been stung in such a way as usually to be para- 

 lyzed, without being actually killed. The various species of 

 Sphecina frequently select particular species of insects or 

 spiders as food for the young. Pepsis formosa (Pompilidae) 

 uses tarantulas for this purpose; Sphccins speciosns (Bembe- 

 cidse) stores her nest with a cicada; Nyssonidse pick out cer- 

 tain species of Membracidse ; mud-daubers (Sphecidae) use 

 spiders; and other families of Sphecina capture bees, beetles, 

 plant lice or other insects, as the case may be. The solitary 

 wasps (Eumenidse) are similar to the digger wasps in habits. 



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

 of cutting pieces out of rose leaves; it uses oblong pieces to 

 form a thimble-shaped tube which, after being stored with pol- 

 len and nectar, is plugged with a circular piece of leaf. The 

 larval cells are made either in tunnels excavated in wood by 

 the mother or else in cracks or other chance cavities. 



