IX 



these old forms (Parnassius, Doritis, Zegris) belong tho the Papiiionidae, and 

 further as regards the chrysalides, to the succincti ; for they are also fastened 

 by a girdle-thread, which is not the case with the Heterocera, to which, for 

 the rest, they are allied in this respect. 



At least this is not the case with those more highly developed Heterocera 

 from which the Rhopalocera must have been differentiated ; among their lower 

 forms however, in particular among some Geometrae, we also find such a girdle- 

 thread ; but here the question turns only on a phenomenon of convergence. 



Accordinglv it follows from this that succincti, as the Rhopalocera of the genus 

 Papilio — in the still unknown metamorphosis of a species of which, P. Coon F., 

 I have been able to observe a still more developed spinning-power — as regards 

 the development of the said power stand midway between the more powerful, 

 occurring among the old forms of Papiiionidae and the more reduced in the 

 families which are therefore counted by Boisuuval among the suspensi; in 

 this we clearly see three degrees of development and hence the gradual, 

 evolutional decay of the power in question. And what do we see in the 

 chrysalides of the Hesperidae? They have in this respect reached the very 

 same stage of evolution as the above-mentioned old forms of the Papiiionidae. 

 In them also the spinning-power is rather strongly developed, in one species 

 more than in another and in many the pupae are still surrounded by a good 

 deal of loose cocoon. Besides this they are always fastened both at the anal 

 extremity and by a girdle-thread ; they are indeed real succincti. If Bois- 

 DUVAL had been better acquainted with this, he would only have been able to 

 maintain his class of involuti as a subdivision of the succincti. It appears, 

 therefore, that the Hesperidae, in this respect also, are much more to be 

 considered as belonging to the Rhopalocera than to the Heterocera. Finally 

 this is also borne out by the form of the pupae. Some of the chrysaUdes of 

 the Hesperidae, their colour cooperating in this, as those of Odontoptilum 

 Angulatum Feld., strongly remind us of those of pupae of the genus Pieris, 

 but in all of them the form is generally much more allied to those of the 

 Rhopalocera than to those of the other group. The angular sharp-edged 

 thorax often provided with a pointed head-process, is in a somewhat modified 

 form also found in other Rhopalocera, but is quite different from what in this 

 respect is found in the Heterocera. On these grounds I believe I am fully 

 justified in continuing to reckon the Hesperidae among the Rhopalocera 

 and also to devote a monograph to this genus. To avoid the less exact 

 name of Rhopalocera for the Hesperidae a main division has of late, again 

 been adopted viz. Diurna, which has again been subdivided into two sections, 

 the Rhopalocera and the Grypocera, then denoting the Hesperidae by this 



