11 



its presence in pantries, storehouses, and bakeries, give it really a 

 greater economic importance than any of the other species. 



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 

 Eastern towns and colleges. The characteristics of the diflferent 

 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 (Evania appendigaster L.). 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 ichneumonfly (Entedon liagenowiRsitzh.) , 

 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 anijuals are 

 inclosed in a room overnight they will effectively clear it of roaches. 



REMEDIES. 



Like the crows among birds, the roaches among insects are appar- 

 ently unusually well endowed with the ability to guard themselves 

 against enemies, displaying great intelligence in keeping out of the wny 

 of the irate housekeeper and in avoiding food or other substances 

 which have been doctored with poison for their benefit. Their keen- 

 ness in this direction is unquestionably the inheritance of many cen- 

 turies during which the hand of man has ever been raised against 

 them. 



[Cir. 51] 



