PELOP^EUS SPIRIFER. 205 



Among the insect nests in the British Museum is a fine example 

 of the burrow made by a Brazilian member of this genus, Xylocopa 

 grisescens. It is a very large insect, and the hole is so wide that it 

 will easily admit a man's thumb. There is in the same case a nest 

 of a curious Australian bee, Lestis bombylans. 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 thick- 

 ness of the wood on one side, and only one fourth on the other. 

 All the cells are filled with bee-bread. 



Ix 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 Sphegidas. It is rather a pretty insect, though formi- 

 dable in aspect, the body and abdomen being black, and the limbs 

 and long footstalk bright yellow. The genus Pelopoeus 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 com- 

 mon to its kind, the Pelopseus does not make the divisions of wood- 

 chips, as is the case with the Xylocopa, but uses mud for the pur- 

 pose. 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 de- 

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

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

 popidnea 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 farther growth. The lar- 

 va has a small, flat head, a suddenly-enlarged thorax, and a body 

 tapering regularly to the tail. 



