78 INSECT ARTIZANS AND THEIR WORK 



part of the body. This power of movement would 

 make them dangerous company for a dehcate egg 

 placed among them, or even for a newly hatched 

 grub. 



Here, then, is the reason why the egg is suspended. 

 Should it be struck by the movements of one of 

 the caterpillars, it would swing out of the way 

 like a pendulum, and the newly hatched and tender 

 grub can feed in safety from its swinging perch. A 

 remarkable point in this connection, showing how 

 several items are correlated, is the way in which 

 the egg-shell splits up on hatching. From the 

 point of attachment of the suspensory thread it 

 splits into a sort of ribbon which in effect lengthens 

 the thread and enables the grub to get nearer to 

 its food. 



Eumenes unguiculata, though it fashions a less- 

 regular vase, provides three cells in the interior, 

 each of which has its egg and its store of cater- 

 pillars. An Indian species, Eumenes conica, makes 

 the mistake of constructing its nest with walls so 

 thin that a parasite readily pierces them to lay 

 its eggs. For this reason only two wasps were 

 reared from a group of five cells, the parasites 

 having destroyed the other three. 



Several species of Trypoxylon (all the species are 

 Masons) construct nests much after the pattern 

 of Eumenes. One of these is mentioned by Bates 

 in the account of his natural history exploration 

 of the Amazons. He says : 



" Their habits are similar to those of the Pelopcsus : 



