xxxiii, '22] ENTOMOLOGICAL NEWS 111 



it means that they have spread into a region where life condi- 

 tions are not optimum. 



The primitive color in the genus appears to have been brown 

 because, 1. scuiifasciata is brown; 2. the females of several of 

 the species are brownish ; however, the gray and yellow color 

 pattern of the high Group 8 (d) is found also in the genus 

 Ortlietnun. Apparently the bright reds of auripcnnis and of 

 saturata have developed independently of each other.. 



Probably the primitive wing had three broad spots or bands, 

 basal, nodal and apical, but just how this pattern is handed 

 down through the various lines is baffling. These band? in 

 whole or in part may disappear in a series to reappear in some 

 apical species. They may disappear in one sex, as in the female 

 of lydia^ or may appear in individuals of a species usually 

 without them, as in the form pracnubila of 4-inaciilata. Per- 

 haps their genes are always present but are inhibited at times 

 by other factors. 



The writer believes that the genitalia in this genus show rela- 

 tionships so clearly that the subgenera can be defined by them. 

 They certainlv can be lined up much better than they were by 

 ECirby. 2 The writer's views are substantially those indicated in 

 Ris' key to this genus in his Libcllnlincn in the "Coll. Zool. du 

 Selys." The species fall into ten subgenera, as follows: 



1. EOLIBELLULA subgen. nov., type I= scuiifasciata. 



2. BELOXIA Kirby, type =r foliata; includes also saturata. cro- 



ccipciinis and hcrcnlca. 



3. SYNTETRUM subgen. nov., type : angdina. 



4. LIBELLULA Linn., type : 4-inaculata; includes pracnubila 



and probably basilinca. 



5. LADOXA Needham, type =: c.ritsta; includes also Julia and 



deplanata. 



6. PLAT IT EM is Hagen. type ' r lydia; includes also snbonwta. 



7. PLATETRUM Newman, type == dcpressa. 



8. EUROTITEMIS subgen. nov., type : fitl-va; includes, prob- 



ably, poutica. 



9. NEOTETRUM subgen. nov., type : forcnsis; includes also 



pulchcUa and nodisticta. 



10. HOLOTANIA Kirby, type a.viUcna ; includes also com 

 posita. jcsscana. flcrcida, auripennis, Inctnosa, cvanca. 

 couianciic, inccsta and ribrans. 



25 Kennedy, Odonata of Kansas, Bull. Kans. Univ., vol. 18, pi. VII, 



figs. 108-110, 1917. 



26 Kirby, Revision of the Libellulinae, 1889. Catalogue of the Odonata, 

 1890. 



