Tin; FAMILY PAI'ILIOXIDAK. 1029 



hirgo ])ri)j)ortion of tlie Xew Engliuid jjenera is represented in tlie Old 

 World citiier Uy species of the same t>eniifi or i)y eiosely allied genera; yet 

 with the exception ot" one recently introduced no identical species are 

 known.* 



In structure, tiie Papilionidae show an approach to the lower Lepi- 

 doptera. The front legs of both sexes are ef|ually perfect and are always 

 used in locomotion. A large number are provided, as in the Hesperidae, 

 with a lanceohite appendage upon the fore tibiae. Tiie caterpillars are 

 never spined, but either naked, s[)arsely pilose or provided with fleshy 

 filaments. They are usually solitary, but there are occasional instances of 

 gregarious caterpillars in botii divisions of the family. The chrysalids are 

 attached by the tail and by a loose girth around the middle, and, in a few 

 instances, are enclosed in a fragile cocoon. 



In one instance the mode of suspension is altogether unique. In all 

 the three species of the genus Thais found in Europe, the anterior 

 extremity of the chrysalis is furnished with a double tubercle, bristling 

 with short curving hooks, and tlie chrysalis, besides being attached in the 

 normal way of the Papilionidae by the hinder extremity and the girth 

 around the middle, has also an additional support by the entanglement of 

 these anterior liooks in a loop of silk, spun by the caterpillar in preparing 

 for pupation and which seems to spring from about the same point as the 

 transverse loop of the thorax. There seems to be very little reference to 

 this peculiar mode of suspension by those who have treated of this 

 genus, although it was distinctly mentioned by Rambur as long ago as 

 1840 in his Faune entomologique de TAndalusie. Boisduval, Rambur and 

 Graslin in their work on European caterpillars describe and figure two 

 species and Duponcliel gives an independent description and figure of one 

 of them, — all without reference to this peculiar mode of suspension or to 

 the unique structure of the anterior extremity, to which there appears to 

 be no parallel in the Lepidoptera. Rambur, in the work referred to, writes 

 to this effect : the anterior extremity which is pointed and bifid is also fur- 

 nished with little short thick hooks, which hook themselves in two bundles 

 of thick silk and it is thus supported bj' the two extremities besides l)y the 

 light band of silk which embraces it. Yet Doubleday in 1846 says that 

 "according to Dr. Rambur, when about to undergo their metamorphosis 

 they not only fasten themselves by a transverse thread like the Parnassii, 

 but also surround themselves by a very slight silken web," which Rambur 

 nowhere asserts, and which is an entire mistake. Hiibner figures the 

 chrysalids of T. polyxena with the cremaster raised and quite free of 

 silken attachments. 



Il» afBnities. As the relations of this family to others have been the 

 subject of much dispute, it may be well to point out in more detail than 



•Doubts, however, have been expressed concerning the distinction of several species. 



