2 42 Annals Entomological Society of America [Vol. 11, 



Note. — The capture of males of L. archippus in which the black 

 stripe teas ivanting from the upper surface of the hind iving, and of 

 transitional forms of both sexes at Albany, N. Y., by John H. Cook. 



Mr. Cook first met with the stripeless form in June, 1898, near 

 Hudson, X. Y. A second specimen was captured near his home in 

 Albany in 1901 and a third in the same field in the following year. 

 This latter was a beautiful specimen apparently only just emerged 

 from the pupa. Mr. Cook's attention was now thoroughly aroused 

 and he collected assiduously at Albany during three seasons, always 

 working on the best ground to the west of the city, and taking over 

 90 specimens with the stripe wholly or nearly suppressed. The fol- 

 lowing conclusions were reached: — (1) All the stripeless archippus 

 captured were males; (2) The females shared the tendency but never 

 reached the extreme found in the other sex; (3) Most of the individuals 

 taken showed some weakening of the stripe, varying from a slight break 

 (most commonly between veins III and V2 and between V3 and VII2, 

 of the s)''stem of Comstock and Needham) to complete suppression on 

 the upper surface ; (4) At Albany individuals with a broken stripe 

 outnumbered those with an entire stripe in the proportion of about 

 18 to 1, while stripeless specimens were taken in the average propor- 

 tion of 1 to 14. Mr. Cook also collected data from other localities and 

 endeavored to interest correspondents in the problem. Including the 

 Albany material he secured records of about 1600 specimens and was 

 able to reach the conclusion that in New England and the Middle 

 States broken-striped individuals are not uncommon though generally 

 outnumbered by those with a continuous stripe. He did not meet 

 with any record of a perfectly stripeless form except for his own obser- 

 vations and the two specimens to which the name pseudodorippus 

 has been given. vStrecker's type of this form exists in Dr. W. J. Hol- 

 land's collection [Butterfly Book, New York [1899], 185). These two 

 pseudodorippus were also taken in the Eastern vStates (the Catskill 

 Mountains, and in Massachusetts), but Mr. Cook, who has seen one and 

 received from Dr. Holland an account of the other, believes that the 

 disappearance of the stripe is here part of a general blurring of the 

 colour-scheme in which some elements are obliterated and there is a 

 tendency towards the invasion of one colour-area by another. The 

 extreme varieties captured by Mr. Cook himself, did not, on the other 

 hand, differ at all from the normal archippus except in the absence of 

 the black stripe from the upper surface of the hind wings. To this 

 stripeless variety Mr. Cook and Mr. Watson have given the name 

 lanthanis. Mr. Cook's accurate data and most of his specimens were 

 unfortunately destroyed when the college buildings at Albany were 

 burnt down on Jan. 6, 1906. It is much to be hoped that he may be 

 able to continue his most interesting observations in this favourable 

 locality, and that naturalists may be stimulated, by these reeords, 

 now by Mr. Cook's kindness made public for the first time, to work 

 in other North American localities. 



