244 



NATURAL HISTORY 



bees carry pollen. These bees build their nests in hollow trees, and the 

 clay is used to build up a wall closing the crevice, all except the opening 

 for their entrance and exit. Another allied species uses sticks and dried 

 leaves instead of mud to stop the hole, cementing them together with a 

 "•urn which it gathers from one of the forest trees. 



Bugs. 



The term bug is used in different senses by naturalists and by the 

 general public. In England it is generally restricted to one species — the 

 form which is so apt to infest beds in uncleanly houses, while with us 

 almost any insect or larva may be called a bug. The naturalist, however, 

 restricts the term to a certain group of insects which in the more precise 

 terminology of science are termed Hemiptera. The bugs are characterized 



by having the mouth parts adapted for sucking and 

 piercing. As shown in the cut, they form a needle-like 

 tube which is kept between the legs when at rest, but 

 which can be directed in almost any way when the 

 occasion offers. The wings also differ from those of 

 other insects. In all they have a peculiar type of ar- 

 rangement of the little nerves or veins which strengthen 

 them, while the first pair may be to a certain degree 

 modified into wing-covers corresponding to the elytra 

 of the beetles. In the group of bugs most studied these 

 win^-covers are hardened at their base, while the half 

 more remote from the body is membraneous, and it is 

 to this fact that the term Hemiptera (half-winged) 

 applies. It is to be noticed in passing that 

 some of the bugs are without wings, but 

 still in all the rest of their structure they 

 a«ree with the others. 



In number of species the bugs rank next to the beetles 

 and flies, Mr. Uhler estimating them at fully fifty thousand. 

 Still, mere numbers do not make a group interesting, and so 

 little have the habits of these forms been studied that we shall 

 dismiss them with but brief mention. 



At the bottom of the series of bugs come some forms which 

 live as parasites on various mammals, and which are known as lice. Their 

 habits have, indeed, extensive modifications of structure. The wings have 

 been lost while the feet have been modified for holding on to the hair, so 

 that they resemble the pipe-tongs which the gas-fitter uses and are admi- 



Fig. 229. — Under surface 

 of a cicada, showing the 

 piercing , and sucking 

 beak extending back be- 

 tween the legs. 



Fig. 2 



-Head- 

 louse (Pedicu- 

 lus capitus). 



