THE LEAF BUGS. 661 



in his Catalogue from America north of Mexico, and Knight 

 and others have since described one hundred or more from 

 the same region. They are, for the most part, plant feeders, 

 but a large number prey upon the young or soft-bodied forms 

 of other insects. Of their habits Knight (1923. 422) has said: 



"The predaceous habit is only partially developed in certain species, 

 and thus animal blood serves merely to supplement the sap obtained 

 from particular food plants. Probably the greater number of species 

 are limited to a single host plant, or to a genus of plants, while a very 

 few, such as Lygus pratensis Linnaeus and Haitians citri Ashmead, have 

 a wide range of food plants. Forms which are chiefly predaceous are 

 more frequently found on miscellaneous plants. Even among species 

 which always breed on a single host plant, a general dispersal of in- 

 dividuals usually takes place. Following the time of emergence and 

 mating, individuals of Tropidosteptes cardinalis Uhler, Lopidea staphy- 

 lese Knight, and others, have been observed to migrate from their host 

 plant to shrubbery in the general vicinity; from thence they doubtless 

 become dispersed over wider territory and to new plants, although in 

 the normal course of their life, eventually returning to suitable growth 

 of the preferred host plant for the purpose of oviposition." 



The literature treating of our eastern species of Miridae is 

 widely scattered. The principal papers used in the prepara- 

 tion of the text which follows are those by Reuter, 1876, 

 1878, 1904, 1909, 1910, 1912a, 1913; Distant, 1883; Uhler, 

 1887, 1887a, 1887b, 1890, 1892, 1901; Kirkaldy, 1902, 1902b, 

 1906, 1906a; Van Duzee, 1916a, 1916b, 1916c, and the numer- 

 ous papers of Knight cited in the bibliography near the end 

 of this volume. In this work 467 species and numerous varieties 

 of Miridae are described from the eastern states. 



Our eastern species are separated by Knight (1923, 425) 

 into nine subfamilies, the following being a modification of 

 his key so as to bring the sequence (with the exception of 

 the Orthotylince) as near to that of the Van Duzee Catalogue 

 as possible. In my keys under the subfamily headings I have 

 but rarely, however, used the characters pertaining to the 

 male genitalia in the separation of either genera or species. 

 Students desiring to so use them are referred to Dr. Knight's 

 works, especially the one in the "Hemiptera of Connecticut." 



KEY TO EASTERN SUBFAMILIES OF MIRID.E." 



a. Arolia present, erect and prominent, approximate at base between 

 the claws (figs. 33—60). 

 b. Arolia divergent or divaricate and frequently dilated towards their 

 tips (figs. 55 — 60) . 



7 The figures cited in this key refer to those on Plate X. 



