— 109 — 



What Makes a Species in the Genus Arctia.* 



By John B. Smith. 



IMr. Stretch has asked this question, not so long ago, and answered 

 it in a manner eminently unsatisfactory to himself and to others. He, 

 however, gave in great detail a list of features which are not sufficient to 

 make a species ; including in this category maculation or color of second- 

 aries, of abdomen, and of primaries to some extent. Messrs. Hulst and 

 Neumoegen have discussed the question of specific identity of some forms 

 recently, and they have not agreed in result at all. 



In arranging the Nat'l. Museum material, I followed the order of Mr. 

 Grote's List, and while putting in the species tried to discover the reason 

 for the sequence adopted — without much success I must say. It appeared 

 to me then, that a better scheme was possible — ^something like that pro- 

 posed by IMr. Stretch in his book on the Zygaenidce and Bombycid^. I 

 think too, that I found an answer to Mr. Stretch's question, which will 

 decide many cases, and that is, that specific characters are found in modi- 

 fications of the pattern of markings of the primaries. The secondaries 

 may be indifferently red or yellow, sometimes black — the body may be 

 maculate or immaculate, withf)Ut affecting the species ; but the pattern 

 of markings of primaries remains constant. The markings may vary 

 verv largely in completer.ess, but some peculiarity — the specific character — 

 sticks. I will now say however that I have ik>i examined the species in any 

 wa}" except as to maculation, and while I am confident that other and belter 

 characters wid yet be discovered, yet still they will, I am equally confident, 

 confirm the conclusions reached from a careful study of the maculation. 



According to pattern of maculation the first series in the genus would 

 be that in which all the veins are marked with yellow or white. All of 

 these species have toward the outer portion t)f the wing a ^ shaped mark. 

 Virgiincida and qucnselln iWfitr at once from all the others of the group 

 by lacking the transverse line at the back of this W. All the others have 

 this line in more or less perfection. Virgimcttla is large, broad winged, 

 with vellow^ secondaries. Qtiensellii i?, ^iwaW., narrower winged, with gray 

 secondaries. The synonomy of the latter is involved. The species have 

 the pale lines narrow, as is also the pale margin. 



The next point of difference in maculation which will serve as a 



basis of further subdivision is in the cross bands. Usually there are two 



of these, sometimes three and they are very variable in extent and in 



completeness. Yet, variable as they are, they aff'ord a safe character — so 



far as my observations go at least. In the first series none of these cross 



bands ever go below the submedian pale streak. If a line is partly ob- 



* Read before the Ent. Club A. A. A. S., August, 1887, reprinted as part of the- 

 Proceedings of that Club. — Ed. 



Entomologica Americana. Vol, hi. 17 September, 1887. 



