1370 THE BUTTERFLIES OF NEW ENGLAJTO. 



expand; third, the wings are all expanded. The great majority of the South 

 American species belong to the first of these divisions such as Pyrrhopvga, Erycides, 

 Goniurus, Goniloba and some species of Paraphila [corresponding in general to the 

 higher Hesperidi]. To the second very few South American Hesperidae belong, prin- 

 cipally of the genus Pamphila [corresponding to the Pamphilidi]. The third compre- 

 hends a very peculiar group of insects consisting of the genera Pyrgus, Nisoniades and 

 Achlyodes [corresponding to the lower Hesperidi]. They have the upper wings more 

 or less convex and never erect them in repose* and they will, I believe, form a very 

 natural subdivision of the family. 



They generally develop slowly, frequently having but a single genera- 

 tion in the course of the yearf ; very frequently (perhaps generally?) they 

 hibernate in the chrysalis state, but there are a considerable number, which, 

 though full grown in the autumn, do not change at this epoch, but, remain- 

 ing dormant through the winter, undergo their transformations in the early 

 spring before vegetation has started. None are certainly known to pass the 

 winter either in the egg or the imago state. 



A single species of each division of the family has been found fossil in 

 the tertiaries of Europe, one in the oligocene of Provence, and the other 

 in the more recent deposits on the Ehine. 



The division of the family. The classification of the Hesperidae 

 has proved a stumbling-block to all who have proj)osed any arrangement 

 of butterflies. Until recently no author, Hiibner excepted, has even at- 

 tempted more than a generic collocation, J and most essays of the latter 

 sort have been exceedingly unsatisfactory. In his Verzeichniss bekannter 

 schmetterlinge, Hiibner divided the "stirps" into eight "families"; the 

 first three of these are founded mainly on the form of the wings, the others 

 simply on their markings ; these divisions are almost wholly unnatiu-al, 

 although the sequence of the genera is far more reasonable than that of 

 Herrich-Schaeffer or of Butler. 



Fabricius was the first to separate the family into distinct genera. In 

 Illiger's Magazine he divided it into three genera — Thymele, Helias and 

 Pamphila. Helias was founded upon a single, undescribed and now un- 

 known species. If we omit Helias, the genera Thymele and Pamphila 

 will represent in the main§ the natural separation of the Hesperidae into 

 two grand divisions, which are of less value than subfamilies, and may 

 therefore be termed tribes ; to the former we may apply the name Hes- 

 peridi, and to the latter Pamphilidi. The following distinctions will be 

 found between the two tribes : — 



•This is not strictly true either of European Hesperidi being single brooded while the spe- 



or North American species of these groups. cies of Erynnis and Augiades are double 



t Dupouchei (Incouogr. des chenilles, 211) brooded, 



remarlts of the European Hesperidae that the J Latreille in the Encyclop6die mfithodique 



species with tawny ground color are single separated the species into unnamed groups by 



brooded, while those having la darii ground an analytical table, based principally on the 



spotted with white are double brooded; but form and markings of the wings. 



not only can this statement not be extended be- § Some species enumerated under Pamphila 



yond Europe, but ills not even true there, many belong to the first division. 



