64 FAMILY II. BLATTID^B. THE COCKROACHES. 



are divided among nine subfamilies and 26 genera. Aside from 

 several subtropical forms, which are often introduced in bananas 

 and other fruit, but which soon die, and are, therefore, considered 

 only as adventives, 30 species and two varieties or races are recog- 

 nized as residents of the territory covered by this work. These 

 represent ten of the subfamilies and 19 of the genera recognized 

 by Hebard. Of the 30 species, 12 are established adventives, the 

 other 18 being native or indigenous species, as are also the two 

 races. In addition to these, three of the adventive species repre- 

 senting one additional subfamily and two genera, are included, as 

 they are so frequently introduced with tropical fruits that they 

 will probably be seen by many of our future students. 



Aside from the general works on Orthoptera cited in the 

 Bibliography, the principal literature treating more or less ex- 

 tensively of the Blattid.p occurring in the Eastern United States 

 is as follows: 



Saussure, 1863, 1869a, 1870, 1872 ; Brunner, 1865 ; Rehn, 1903, 

 1903a, 1903b; Shelf ord, 1906, 1907, 1907a, 1908, 1908a, 1910a; 

 Behn & Hebard, 1910 ; Caudell, 1913 ; Hebard, 1916a, 1916b, 1916c, 

 1917a. 



The following key to subfamilies is mainly a composite of 

 parts of those of Scudder (1897c, 12), Caudell (1913, 600) and 

 Hebard (1917a, 11 22), the last named being a key to genera and 

 species only. It must be remembered that a subfamily is only an 

 artificial individual concept created for the purpose of facilitat- 

 ing the systematic naming of the species of any group. Subfami- 

 lies do not exist in nature and the recognition of them here is only 

 to render shorter and more easily followed the keys to the genera 

 of which they are composed. The characters of chief importance 

 generally used in separating the subfamilies of Blattidse are those 

 pertaining to the armature of the lower border of the femora, the 

 structure of the tegmina and wings, the form of the supra-anal 

 and subgenital plates and the presence or absence of arolia and 

 pulvilli. To these have been added other characters pertaining to 

 size, color, etc., in order to enable beginners to more easily place 

 their specimens. 



KEY TO EASTERN SUBFAMILIES OF BLATTID.E. 



a. Middle and hind femora armed beneath along one or both margins 

 with two or more distinct spines; tegmina present, often abbreviat- 

 ed in the female. 

 ?). Pronotum and tegmina smooth or but sparsely haired or pilose. 



