282 OUR HOUSEHOLD INSECTS 



of insects, but not for the Heteroptera, in which sub- 

 order alone we find antennae composed of a small number 

 of long joints. Like all the rest of the body, the bug's 

 antennae are clothed with hairs, which are, no doubt, 

 more or less sensory in function ; those on the basal 

 joints are much coarser and more thickly set than those 

 towards the tip. The last joint, as will be observed 

 from the figure, is slightly clubbed at the end, and is 

 probably the most highly sensitive part. 



The eyes are black and very prominent, appearing as 

 two masses like little blackberries at the sides of the 

 head, reminding one of the corresponding organs in 

 certain small ant-like beetles (Pselapliidce) which inhabit 

 moss or lurk under stones. The bed-bug is somewhat 

 exceptional amongst Hemiptera in not possessing, in 

 addition to its compound eyes, the small simple ones 

 called "ocelli." Two such are usually to be found, in 

 this order, between the compound eyes, but our present 

 insect is destitute of them. 



The thorax, or, as we ought rather to say, the pro- 

 thorax (Fig. 90), is curiously shaped, being much wider 

 than long, and having broad leaf- 

 like expansions of its chitinous 

 covering at its sides. These run 

 forward by the side of the head 

 almost as far as the eyes, and 

 so form a notch into which the 

 h ead loosely fits, and whereby its 

 lum - sideward motion is considerably 



restricted, as if by a stiff collar. A similar peculiarity, 

 viz., the winged margin to the thorax, will be familiar 

 to microscopists as occurring in the little lattice-winged 

 insects called " thistle-bugs " (MonantJiia cardui), which 

 are found abundantly on thistle-heads, and are often 



