470 Dr. T. A. Chapman's Contributions to 



much higher, but suitable localities, i. e. areas of food-plants, 

 did not happen to be met with. The (^ (^ were seen abun- 

 dantly during the whole period noted, July 21 to August 

 5, but it was only towards the end of the period that the 

 $ $ were seen in any numbers. 



Though the larva of P. eros is quite properly described 

 as hitherto unknown, it is the case, as I learned from 

 M. Rondou when I saw him this summer (1914), that he 

 had bred P. eros from larvae found on Oxytropis pyrenaica, 

 a plant closely resembling Pliaca astragalina (or a plant 

 very close thereto, on which eros feeds at Le Lautaret), 

 one of the alternative foods on which P. eras larva feeds. 

 In admitting some haziness as to this plant, I must plead 

 that there are a good many species, or at least several, 

 that are so much alike, that I at least cannot distinguish 

 them when only the leaves are available. 



In both 1912 and 1913 I succeeded in getting a fair 

 number of larvae to go into hibernation, but failed to bring 

 any through the winter of 1912-1913. The following 

 winter I was more successful, by means of keeping the 

 larvae iced during the winter, and bringing them up early 

 and forcing them, as I found they were beginning to die 

 off. Of these I succeeded in getting only one into its 

 last instar, when it also finally died. The unsuccess 

 was probably facilitated by the food-plant having to be 

 forced as well as the larvae and was rather drawn up and 

 succulent. 



Eggs were laid at the end of July by females taken on 

 the Route de la Thouviere, Val d'Isere; the males were 

 common in many places near Val d'Isere, the females were 

 however rather scarce. The young larvae hatched during 

 the first week in August, they were placed on Oxytropis 

 campesfris and eat it readily; the eggs also were laid on 

 this plant, but not on any other ofiered them, this was 

 suspected to be the (or a) food-plant from being present 

 wherever the butterflies were at all common. They after- 

 wards eat also a plant that was brought home last year 

 as Phaca astragalina as food for L. pheretes, but was seen 

 this spring to be different from other specimens brought 

 as that plant. It was supposed to be possibly Hippocrepis, 

 which it very closely resembles, but is seen to possess a 

 more hairy leaf with a raised midrib below (flowers not 

 seen). At any rate eros eats it readily, but will not look 

 at Phaca or Hippocrepis. 



