and in the bindinp; of books is to them very attractive. The surface of 

 the covers of cloth-bound books is often much scraped and disfijijured, 

 particuhirly by the German cockroach (BlatteUa germanica) , and the 

 gold lettering is sometimes eaten off to get at the albumen paste. On 

 shipboard the damage is oftefn very extensive on account of the vast 

 numbers of cockroaches which frequently occur there, and we have 

 reliable accounts of entire supplies of ship biscuits having been eaten 

 up or ruined by roaches. 



The damage they do is not only in the products actually consumed, 

 but in the soiling and rendering nauseous of everything with which 

 they come in contact. They leave, wherever they occur in any num- 

 bers, a fetid, nauseous odor, well known as the '^roachy" odor, which 

 is persistent and can not be removed from shelves and dishes without 

 washing with soap and boiling water. Food supplies so tainted are 

 beyond redemption. This odor comes partly from the excrement, but 

 chiefly from a dark-colored fluid exuded from the mouth of the insect, 

 with which it stains its runways; and also in part, doubtless, from the 

 scent glands, which occur on the bodies of both sexes between certain 

 segments oT the abdomen, and which secrete an oily liquid possessing 

 a very characteristic and disagreeable odor. It frequently happens 

 that shelves on which dishes are placed become impregnated with this 

 roachy odor, and this is imparted to and retained by dishes to such an 

 extent that everything served in them, particularly liquids, as coffee or 

 tea, will be noticed to have a peculiar, disgusting, foreign taste and 

 odor, the source of which may be a puzzle, and will naturally be sup- 

 posed to come from the food rather than from the dish. 



The roaches are normally scavengers in habit and may at times be 

 of actual service in this direction by eating up and removing any dead 

 animal material. 



One other redeeming trait has been recorded of them, namely, that 

 they will prey upon that other grievous pest of houses which are not 

 subjected to careful supervision, the bedbug. Their habits in this 

 direction have been recorded several times. One writer, in a narrative 

 of a voyage (Foster's Voyage, Vol. I, p. 373), makes the following 

 statement in this connection: 



Cockroaohea, those nuisances to ships, are plentiful at St. Helena, and yet, bad 

 as they are, they are more endurable than bugs. Previous to our arrival here in 

 the Chanliclcrr, we had suffered j^reat incoiivenienre from the latter, but the cock- 

 roaches no sooner made their api)earance than the buj^s entirely disappeared. The 

 fact is that the cockroach preys upon them and leaves no sign or vestige of where 

 they have been. So that it is a most valuable insect.' 



The cockroach is, however, far too much of a nuisance itself to war- 



' Proc. Ent. Soc. Lond., 1865, N. S. 3, p. 77. 

 [Cir. 51] 



