PELOP^US SPIEIFER. 185 



genus, Xylocopa grisescens. It is a very large insect, and the 

 hole is so wide that it wiU easily admit a man's thumb. There 

 is in the same case a nest of a curious Australian bee, Lestis 

 hombylans. The insect is very like a humble bee, but remarkable 

 for the bright steel-blue of its body, and the absence of hair. 

 The burrow runs through a branch, but is not in the centre, 

 having at least three-fourths of the thickness of the wood on one 

 side, and only one-fourth on the other. All the cells are filled 

 with bee-bread. 



In the upper right-hand corner of the illustration may be seen 

 a curious-looking insect, having its abdomen at the end of a very 

 long footstalk. This is the Pelopceus spirifer, an insect belonging 

 to the family Sphegidse. It is rather a pretty insect, though for- 

 midable in aspect, the body and abdomen being black, and the 

 limbs and long footstalk bright yellow. The genus Pelopaeus is 

 widely spread over the hot parts of the world, and its members 

 are rather diverse in their habits. Many of them are notable 

 builders, using mud as the material with which they make 

 their nest, and will therefore be described under the head of 

 Builders. The present species, however, takes rank as a wood- 

 burrower, and, as may be seen from the illustration, makes a long 

 tunnel inside a branch, and divides it into cells. True to the 

 instinct which seems common to its kind, the Pelopaeus does not 

 make the divisions of wood-chips, as is the case with the 

 Xylocopa, but uses mud for the purpose. Instead of storing her 

 cells with bee bread, she captures spiders, and with their bodies 

 supplies her future young with food, just as is the case with so 

 many earth-boring hymenoptera. 



The last figure in the illustration represents one of the wood- 

 boring beetles, and is given in order to show the curious effect 

 which is produced by its tunnels. The beetle mostly prefers 

 the twigs of the aspen as a home, and its presence can always be 

 detected by the swollen aspect of the injured twig, looking as if 

 the tree were affected with gout. This is a British insect, Saperda 

 populnea by name, and in some places it is extremely injurious 

 to the aspen and poplar, always choosing the second or third 

 year's wood, and effectually spoiling its further growth. The 

 larva has a small, flat head, a suddenly enlarged thorax, and a 

 body tapering regularly to the tail. 



