364 THE CANADIAN ENTOMOLOGIST 



preoccupied), is introduced to include nearly all of the native 

 species commonly placed in Ischnoptera, this genus together with 

 Blattella having been found to contain many valid generic units. 

 Only one true Ischnoptera, I. deropeltiformis (Brunncf), belongs 

 to the North American fauna, while the only species of Blattella 

 represented in the New World is the introduced and cosmopolitan 

 genotype, B. germanica (L). 



A valuable feature of the work is the careful definition of the . 

 characters of diagnostic value, including the methods of measure- 

 ment. The venational terminology, which is illustrated by a 

 diagram of a typical blattid tegmen and wing, is that which has 

 been commonly employed by orthopterists, but in the present 

 writer's opinion it is somewhat to be regretted that the more 

 generally applicable system of Comstock and Needham was not 

 substituted. 



Although detailed descriptions of genera and species have 

 been avoided, the characters of real importance have been carefully 

 analyzed and much attention has been given to coloration and to 

 the range of variation in each species. The geographical dis- 

 tribution is also treated in great detail, the exact localities with 

 other available data being given for all the material studied. 



Forty-three species are recorded as 'established within the 

 United States and of these ten are probably introduced. Species 

 are numerous only in the limited tropical areas along the southern 

 border of the country, rapidly diminishing northward, there being 

 only two indigenous forms and two established adventives which 

 are known to occur north of the Canadian boundarN*. 



Following the descriptive account of the BlattidcC that are 

 native or naturalized within the territory under treatment is a 

 supplement dealing more briefly with the adventive forms, tropical 

 cockroaches being frequently carried by commerce to more norther- 

 ly localities, where they usually fail to become established. There 

 are thirty -one species in this category, eight of which are also 

 native in southern portions of the United States. 



The extensive series of illustrations are beautifully executed 

 drawings, which leave nothing to be desired. 



Mailed October 1st, 1917. 



