COCKROACHES, ; ili, 
It is very light brown in color, and characteristically marked on the 
thorax with two dark-brown stripes. It is more active and wary than 
the larger species and much more difficult to eradicate. It is the 
smallest of the domestic species, rarely exceeding five-eighths of an 
inch in length, and multiplies much more rapidly than the others, the 
breeding period being shorter and the number of eggs in the capsules 
greater than with the larger roaches. The injuries effected by it to 
cloth-bound reports have been the source of very considerable annoy- 
ance at the Department of Agriculture and in the large libraries of 
Fie. 5.—The German roach (Blattella germanica): a, First stage; 6, second stage; c, third stage; d, fourth 
stage; e, adult; f, adult female with egg case; g, egg case, enlarged; h, adult with wings spread. All 
natural size except g. (From Riley.) 
eastern towns and colleges. The characteristics of the different 
stages, from the egg to the adult, are shown in the illustration (fig. 5). 
NATURAL ENEMIES AND PARASITES. 
In Europe the egg capsules of the cockroach are often parasitized by 
an ichneumon fly.!| This insect has become widely distributed over 
the world following its host insect, and has been redescribed under 
a great many different names. It was found in Cuba as early as 
1829, and has been several times collected in the United States. 
Unfortunately, its usefulness as a means of keeping the roach in 
check by destroying the egg capsules is greatly impaired by the 
occurrence of another ichneumon fly,? which is parasitic upon the 
first. This is also a European species which has been brought over 
with its host parasite. If the true egg-capsule parasite of the roach 
could have been introduced into this country without this secondary 
parasite its usefulness would doubtless have been very much greater. 
The secondary parasite, however, seems to have been introduced 
early, and has been found in Cuba and Florida, and probably occurs 
as widely as its host and prevents the latter from multiplying very 
greatly. Among other natural enemies of the roach are tree frogs; 
and a correspondent informs us that if these animals are inclosed in 
a room overnight they will effectively clear it of roaches. 
l Evania appendigaster 1. 2 Entedon hagenowi Ratzb. 
