4 FARMERS’ BULLETIN 658, 
Rarely do two of the domestic species occur in any numbers together 
in the same house. Often also of two neighboring districts one may be 
infested with one species, while im the other a distinct species is the 
commoner one. The different species are thus seemingly somewhat 
antagonistic, and it is even supposed that they may prey upon one 
another, the less numerous species being often driven out. 
STRUCTURAL CHARACTERISTICS. 
Although among the oldest insects geologically, roaches have not 
departed notably from the early types, and form one of the most per- 
sistent groups among insects. The house species are rather uniformly 
dark brown or dark colored, a coloration which corresponds with their 
habit of concealment during daylight. They are smooth and slippery 
insects, and in shape broad and flattened. The head is inflexed under 
the body, so that the mouth parts are directed backward and the eyes 
directed downward, conforming with their groveling habits. The 
antenne are very long and slender, often having upward of 100 joints. 
The males usually have two pairs of wings, the outer ones somewhat 
coriaceous and the inner ones more membranous and folded once 
longitudinally. In some species, as, for instance, the black beetle, the 
females are nearly wingless. The legs are long and powerful and 
armed with numerous strong bristles or spines. The mouth parts are 
well developed and have strong biting jaws, enabling these insects to 
eat all sorts of substances. 
HABITS. 
In houses roaches are particularly abundant in pantries and kitch- 
ens, especially in the neighborhood of fireplaces, on account of the 
heat. For the same reason they are often abundant in the oven rooms 
of bakeries or wherever the temperature is maintained above the 
normal. They conceal themselves during the day behind baseboards, 
furniture, or wherever security and partial protection from the light 
are afforded. Their very flat, thin bodies enable them to squeeze 
themselves into small cracks or spaces where their presence would not 
be suspected and where they are out of the reach of enemies. Unless 
routed out by the moving of furniture or disturbed in their hiding 
places, they are rarely seen, and if so discovered, make off with won- 
derful celerity, with a scurrying, nervous gait, and usually are able to 
elude all efforts at their capture or destruction. It may often happen 
that their presence, at least in the abundance in which they occur, is 
hardly realized by the housekeeper unless they are surprised in their 
midnight feasts. Coming into a kitchen or pantry suddenly, a sound 
of the rustling of numerous objects will come to the ear, and if a light 
be introduced, often the floor or shelves will be seen covered with 
scurrying roaches hastening to places of concealment. In districts 
