92 



and in others the spots are so much increased in size that we are 

 compelled to describe the pale markings. It takes five figures to 

 illustrate this species. 



In NemopJiila petrosa, Walker, and its ally from Alaska, the 

 secondaries range from nearly white to entire black, and some 

 five figures are necessary to delineate the range of variation, 

 while in the case of our Californian Leptarctia lena, Boisd., to 

 figure every form it would be almost necessary to figure every 

 example taken, as it is almost impossible to find two alike. In 

 A. Nevadcnsis, Grote, and its variety A.BeJirii, Stretch, the black 

 head and thorax are very striking, but the markings on the wings 

 are very variable, and so I might go on with many more of our 

 Western forms. 



The same difficulty exists among the forms from the Atlantic 

 States, though whether to the same extent I do not know, not 

 possessing equally full material for study. Arge I know to vary 

 greatly, and I should be glad if Eastern students could furnish me 

 with data relative to' A. virgo, Saundersii, Phyllira,Jigurata, celia, 

 nais, and dec or at a. 



So far as I see, the vestiture of the body parts is of great 

 importance, and it would be interesting to know whether, on 

 close examination, these will furnish good specific characters. In 

 all my series of y4. rt<:/^rt/^?, however they may vary above, the males 

 have a uniform pale ornamentation on the body beneath, and on 

 the same parts the females are always black. In AutJiolea and 

 its allies the tip of the abdomen is always black, etc. 



In this connection, I would suggest to Eastern students, 

 who are so situated that they can try the experiment, that 

 much light may possibly be thrown on this intricate question 

 by varying the food of the larvae ; as for instance, take a lot of 

 young larvae of nais, divide them into three lots, feeding one 

 of them on the same food plant throughout, a second also 

 on one plant, though of a different genus — or, what would 

 be better, of a different order if possible — and the third on a 

 variety of plants, changing the species frequently, or keeping a 

 variety in the breeding cage all the time. It would be of great 

 value to note the results, whether one or several forms were 

 produced,, as bearing on the question of what constitutes a 

 species in this group. If possible it would be well to know the 

 parent form from which the larvae were raised. 



If those who possess peculiar forms of any of the Eastern 

 Arctians would send me pen and ink sketches of the markings, 

 it would greatly facilitate my labors, and due credit shall be 

 given ; and at the same time I would ask those who possess good 

 fresh specimens to put on record the results of their examina- 

 tions into the stability of the coloration of the body parts, as a 

 guide to the separation of the species of this and the allied 

 genera, which vary so infinitely. 



