378 PROCEEDINGS OF THE NATIONAL MUSEUM vol. iii 



to the Sehirinae and the Garsaurimae than to the Scaptocormae and 

 Amnestmae. 



A complete Kfe cycle study of one or more species of the Cydninae is 

 a great desideratum. Although only scattered, fragmentary biological 

 notes are available, the probable life history as outlined in the dis- 

 cussion of the family is true, even if very incomplete. 



The separation and definition of the included genera have been 

 difficult, and even yet may be considered far from complete. The 

 search for characters that would permit concise, clear-cut definitions 

 of genera has been only partially successful. The relative value given 

 to any set of characters may vary with workers, so that the included, 

 conservative number of genera may be greatly increased by those who 

 see fit to assign higher taxonomic worth to some of the features here 

 relegated to a position below a genus. In a family as poorly known 

 and as uniform as this one appears to be, any marked structural 

 featm-e presents a great temptation to the worker to establish a genus- 

 regardless of whether the modification has any fundamental value. 

 This type of splitting results in numerous monotypic genera that may 

 be based on secondary sexual characters, adaptive modifications, or 

 even "ornamental" features of a single species. I consider that several 

 monotypic genera of the Western Hemisphere fall in this category and 

 must be suppressed; they are Colobophrys Ilorvdth, Pachymeroides 

 Signoret, Psectrocephalus Van Duzee, and Syllabus Signoret. These 

 are reduced to subgenera or full synonyms in the text, where full 

 explanations are also given. All of these were based on a single super- 

 ficial but prominent character. They all remained monotypic. 



One of the most important and useful characters, used first by 

 Uhler (1877) and later to a lesser extent by Signoret (1881 to 1884), 

 is the modification of the osteole and its peritreme. These features 

 will permit the arrangement of the genera of the world into two groups 

 which, for convenience and to avoid any suggestion of a nomencla- 

 torial position, will be referred to as Groups A and B. 



Group A can be defined as including those genera that sliow a defi- 

 nitely differentiated terminal structure on the anterior part of the 

 osteolar peritreme (figs. 89-100), the differentiation being due either 

 to definite widening of the terminal part or to a marked difference in 

 texture (i.e., being very shniing, polished), or a combination of both. 

 The position of the actual osteolar opening, whether visible ventrally 

 at the base of the terminal lobe or opening posteriorly (not visible 

 ventrally) on the peritreme, also shows some significance. 



Group B would include those genera that do not show any such 

 terminal modification on the anterior part of the peritreme (figs. 

 102-112). In addition, all members of this group have the osteole 

 opening posteriorly on the peritreme so that it is not visible ventrally. 



