il 



tlic completion of the Croton system of waterworks in New York 

 Cit}'. It had probably been introduced long previously, but the 

 extension of the waterworks system and of piping afforded it means 

 of ingress into residences, and greatly encouraged its spread and 

 facilitated its multiplication. The dampness of water pipes is favor- 

 able to it, and it may be carried by the pressure of the water long 

 distances through the pipes without injurj'. This roach has so mul- 

 tiplied in the eastern United States that it has now become the com- 

 monest and best known of the domestic species, and its injuries to 

 food products, books, etc., and the disgusting results of its presence 

 in pantries, storehouses, and bakeries, give it really a greater eco- 

 nomic 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 consider- 

 able annoyance at the Department of Agriculture and in the large 

 libraries of Eastern towns and colleges. The characteristics of the 

 different stages, from the egg to the adult, are shown in the illustra- 

 tion (fig. 5). 



NATURAL ENEMIES AND PARASITES. 



In Europe the egg capsules of the cockroach are often parasitized 

 by an ichneumon ti}^ {Evania appeudigaster). 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 col- 

 lected in the United States. Unfortunately, its usefulness as a 

 means of keeping the roach in check by destroying the e^^ capsules 

 is greatly impaired by the occurrence of another ichneumon fly 

 {Entedon hagenoivi), 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 enclosed in 

 a room over night they will effectively clear it of roaches. 



