140 ILLINOIS BIOLOGICAL MONOGRAPHS [140 



by a distance three times as great as the width of the outer circle of 

 each spot. 



Jasoniades glaucus differs from other species of the genus Jasoni- 

 ades in that the eyespot is single ; that is, it is composed of a circle 

 enclosing a smaller circle and a short rod, but is not associated with a 

 smaller circle dorsad of the large one. The suture bounding the front 

 is bluntly angulated at about the middle. In J. daunus the upper 

 smaller figure of the double eyespot is rounded and the incisions be- 

 tween segments 5, 6, and 7 are marked with more or less distinct black 

 lines. J. eurymedon and J. rutidus have the upper figure of the eyespot 

 triangular and there are no black lines in the abdominal incisions, or 

 else very faint ones. The former has the sides of the front arcuate while 

 those of the latter are straight except for a very slight curve just where 

 they unite. 



Heraclides thoas (^cresphontes) is notable in having a conspicu- 

 ous white mark covering segments 2, 3, and 4 and another on segments 

 7 and 8, while the rest of the body is a variegated reddish brown. 



There remain for the genus Papilio the following species : machaon, 

 hairdii, zolicaon, and polyxenes, all of which are very similar in colora- 

 tion. At the same time there is such variation within species, especially 

 as to the limits of these markings, that any suggestions as to their sepa- 

 ration would be premature. Papilio cresphontiniis, americus, and indra 

 from the southern states and P. hrevicauda from New England probably 

 also belong here but they are so little known that their true position is 

 somewhat uncertain. 



Iphiclides ajax with its numerous transverse bands is quite distinct 

 from all other members of the family. 



Ithohalus. No specimens of the two species of this southern genus 

 have been seen. 



Family Parnassiidae 



The Parnassians seem to be an alpine or arctic group, for their 

 American species are confined to the Rocky Mountains and Alaska. 

 Their scarcity is to be regretted, for they retain many of the primitive 

 characters of the Papilios. While the larvae have acquired osmateria, 

 they still retain verrucae and conspicuous setae which are present only 

 in the earlier larval stages of Papilionidae. As adults also, the venation 

 is of the type found in Swallow-tails but the prolongations of the wings 

 have not yet been developed. The following description is based on 

 Parnassius smintheus of the Pacific States and it agrees in all important 

 particulars with P. apollo of Europe. The only other species recorded 

 south of Alaska is P. clodius. 



Head rugose, black, about one-third the diameter of the abdomen, 



