574 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.46. 



on Monophylla sp.; Arkansas (Hubbard); Missouri (Brown); Ala- 

 bama (Baker) ; Colorado (Baker) ; Arizona (Baker) ; California 

 (Baker). South of United States — Habana, Cuba (Baker); Guada- 

 lajara, Jalapa, Orizaba, Puebia, Oaxaca, Cuernavaca, all Mexico 

 (Crawford); Guatemala (Baker); and Nicaragua (Baker). 



Apparently this species has a veiy wide distribution, and, as might 

 be expected, more or less variation occurs within the species. Van 

 Duzee retains as valid StaFs species concinna as distinct from the 

 more northern form tricarinata Say. A careful and minute studv has 

 been made of the above series of over 200 specimens from the many 

 and varied localities enumerated above, and curves plotted for all the 

 variation characters, namely, the variations in the genital st^^les, the 

 calcar, relative length and size of frons, vertex, pronotum, scutellum, 

 and antennae. If one were to study the forms from Pennsylvania 

 and those from Nicaragua they would probabl}'- be se])arated as two 

 distinct, though similar, species. With all the intermediate localities 

 represented in the series, however, the curves become continuous, 

 and it is at once impossible to recognize the southern forms as distinct. 



There seems to be a general division, not at all sharp, of the series 

 as represented here into three groups, falling geographically into the 

 faunistic regions of the North and West of the United States and 

 northern Mexico, the extreme Southeast of the United States and Cuba, 

 and southern Mexico and Central America. In a very general and 

 loose way it may be said that the individuals of the first region show 

 a tendency toward the following groups of characters: Short-petioled, 

 smaller, pulverulent genital styles, relatively longer pronotum, longer 

 frons, long or short antennae, larger calcar; those in the second 

 region: styles as above, pronotum shorter, frons intermediate, 

 antennae shorter, calcar shorter; those in the far south region (for- 

 merly known as concinna Stal) : longer-petioled, larger, nonpulveru- 

 lent styles, shorter pronotum and frons, longer antennae, smaller 

 calcar. These divisions shade into each other veiy intricately and 

 can not be called even varietally distinct. In the study of specimens 

 in the future these geographic divisions may be borne in mind to 

 some advantage. The most characteristic mark of the species is the 

 maculation of the elytra, although to a certain extent this also is 

 variable, and the form of the male genitalia. 



The largest percentage of the specimens studied are macroperous; 

 fourteen specimens from Kentucky' (collected in May) and several 

 from California are semibrachypterous, having the membrane about 

 half the normal length and reaching only slightly beyond the anus. 

 In these forms the relative measurements are slightly different, as is 

 usually the case in brachypterous specimens. The scutellum is 

 relatively shorter, vertex broader, head often a little narrower than 

 prothorax. The short membrane may or may not be maculate. 

 There are no really brachypterous specimens in the whole lot. 



