90 PRINCIPAL HOUSEHOLD INSECTS. 



from au egg case received from Eagle Pass, Tex., reached the adult 

 stage betweeu March 14 and June 12 of the following year, indicating 

 a period of nearly twelve montlis for comi^lete development. The rate 

 of growth of the roach undoubtedly depends very largely on food and 

 temperature, and under unfavorable conditions 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 (Periplancta americana) (tig. 38) is the native or 

 indigenous species of this continent, originating, it is supposed, in trop- 

 ical or subtropical America. 



The ancient and rather quaint account of this insect^ quoted below 

 in a footnote 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 cosmo- 

 politan, and is unquestionably the most injurious and annoying of the 

 species occurring on vessels. It is sometimes numerous also in green- 

 houses, causing 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 De])artment. The backs, sometimes 

 entirely, of both cloth and leather bound books were eaten off to get 

 at the starchy paste used in the binding. (Insect Life, Vol. I, p. 67-70.) 



It is very abundant in the Middle and Western States, where it has 

 been until recently i^ractically 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 germaniea. In foreign countries it has not become 

 widespread and is largely confined to seaport towns. In size it is 



■ 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, parchment and 

 woollen, but linen and paper. They disappear in Winter, and appear most numer- 

 ous 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 Winter. Some have wings, and others are without — perhaps of 

 diiterent Sexes. (Catesby : Nat. Hist. Carolina, 1748, Vol. II, p. 10.) 



