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What Makes a Species in the Genus Arctia.* 

 By John B. Smith. 



Mr. 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 Xat'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 Mr. Stretch in his book on the Zygsenicke and Bombycidse. 1 

 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, without affecting the species ; but the pattern 

 of markings of primaries remains constant. The markings may vary 

 very largely in completeness, but some peculiarity — the specific character — 

 sticks. I will now say however that I have not examined the species in any 

 way except as to maculation, and while I am confident that other and better 

 characters will 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 of the wing a ^ shaped mark. 

 Virguncula and quensellii differ 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. Virguncula is large, broad winged, 

 with vellow secondaries. Quensellii is small, 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 afford 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 tin- Ent. Club A. A. A. S., August, 1887, reprinted as part of the 

 Proceedings of that Club. — Ed. 



Entomologica Americana. Vol. hi. 17 September, L887. 



