1882. 151 |Hagen. 



W. H. Edwards had commenced the publication of his splendid 

 Butterflies of North America, which now contains the figures 

 of 13 species out of the 23 accepted by him in his last synopsis. 



Notwithstanding all the valuable work mentioned the genus 

 Colias is still a stumbling block for entomologists here and 

 in Europe. Though formerly a large part of the North American 

 species was considered to be identical with European species, this 

 has been strongly denied in later times. 



The breeding of C. Eurytheme and its related forms by the late 

 J. Boll in Dallas, Texas, has been the first step to a better knowl- 

 edge and to a scientific reduction of the species of Colias. Mr. J. 

 Boll had raised C. Eurytheme through two years, 1874 and 1875 ? 

 and had sent in the summer of 1876 his paper accompanied with 

 numerous specimens to Hamburg. The paper was read at the 

 meeting of the Association of Naturalists, Sept. 20, and printed 

 directly in the Tagblatt, p. 176-199. (See Zool. Record 1876, p. 

 146.) The paper has been reprinted twice, in Verhandl. naturw. 

 Unterhalt. Hamburg, 1878, Vol. in, and in Deutsche entom. 

 Zeitschr. Berlin, 1880, Vol. xxiv, p. 241. 



The excellent paper by Mr. W. H. Edwards, N. A. Buttfl., 

 Vol. ii, was the result of similar experiments by N. Am. Lepi- 

 dopterologists. But it should not be overlooked that all those 

 experiments were made only in N. Texas, in Illinois and Nebraska, 

 and that we know the changes of C. Eurytheme only for these 

 regions. The experiments will have to be repeated with the same 

 care in the west, and principally in the north-west and north, 

 before we are sure to know all about C. Eurytheme and its related 

 forms. 



In the same number with C. Eurytheme Mr. W. H. Edwards 

 published his observations on C. Philodice. This excellent paper, 

 though chiefly based upon experiments in West Virginia is very 

 remarkable and should indeed be considered as the standard for 

 the work on all other species of Colias. It is probable that simi- 

 lar experiments on C. Philodice in the north-east and north will 

 considerably enlarge our knowledge. The experiments made in 

 Virginia show from Mr. Edwards explicit statements (p. 5. of 

 the text) that not one of the characters is constant. Nevertheless 

 just the same characters are the only ones used by him and others 



