8 FARMERS’ BULLETIN 658, 
very largely on food and temperature, and under unfavorable condi- 
tions the time required for development may undoubtedly be vastly 
lengthened. The abundance of roaches is, therefore, apparently not 
accounted for so much by their rapidity of multiplication as by their 
unusual ability to preserve themselves from ordinary means of 
destruction and by the scarcity of natural enemies. 
THE COMMON DOMESTIC ROACHES. 
The four roaches which have been made the subject of illustrations 
represent the species which occur most commonly in houses, bakeries, 
or on shipboard. The numerous tropical house species, many of 
which are perhaps only partially domesticated, and the subarctic 
roach of high altitudes and of the extreme north have been omitted. 
The American roach ! (fig. 1) is the native or indigenous species of 
this continent, originating, it is supposed, in tropical or subtropical 
America. 
An ancient and rather quaint account of the American roach 
indicates that this species early came to the notice of our forefathers.? 
Its domesticity doubtless resulted from ages of association with the 
aborigines. It has now become thoroughly cosmopolitan and is 
unquestionably the most injurious and annoying of the species occur- 
ring on vessels. It is sometimes numerous also in greenhouses, caus- | 
ing considerable injury to tender plants. It is a notorious house pest 
and occasionally vies with the German roach in its injuries to book 
bindings. One of the most serious cases of injury of this sort was 
reported by the Treasury Department. The backs of both cloth and 
leather bound books were sometimes entirely eaten off to get at the 
starchy paste used in the binding.’ 
This roach is very abundant in the Middle and Western States, 
where until recently it has been practically the only troublesome 
house species. In the East it is not often so common as are one or 
other of the following species, and especially germanica. In foreign 
countries it has not become widespread and is largely confined to sea- 
port towns. Insize itis larger than any of the other domestic species, 
and it is hight brown in color, the wings being usually long, powerful, 
and well developed in both sexes. 
1 Periplaneta americana L. 
2 The cockroach.—These are very troublesome and destructive vermin, and are so numerous and voracious 
that it is impossible to keep victuals of any kind from being devoured by them without close covering. 
They are flat, and so thin that few chests or boxes can exclude them. They eat not only leather, parch- 
ment, and woolen, but linen and paper. They disappear in winter and appear most numerous in the 
hottest days in summer. It is at night they commit their depredations, and bite people in their beds, 
especially children’s fingers that are greasy. They lay innumerable eggs, creeping into the holes of old 
walls and rubbish, where they lie torpid all the wiater. Some have wings and others are without—per- 
haps of different sexes.—Catesby, Mark. Natural history of Carolina, Florida, and the Bahama Islands, 
v. 2, Appendix, p. 10, London, 1748. 
3U.8. Dept. Agr., Div. Ent., Insect Life, v. 1, no. 3, p. 67-70, September, 1888S. 
