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Vol. XXXVII. LONDON, MARCH, 1905. No. 3 



CONTRIBUTIONS TO THE KNOWLEDGE Oi" NORTH 

 AMERICAN ARCTIID^.— IV.* 



BY O 1' T O S E I F E R T , NEW YORK. 



Arctia proxima, Guerin. — To obtain a feasible knowledge of the 

 extent and direction of variability in this species, extensive material was 

 procured by recrossing original broods and again their inbred progenies. 



Some of the freshly-formed pupae thus obtained were either subjected 

 to treatment by excessive cold (-12° C. for two to three hours repeatedly), 

 or kept at a temperature of about + 4^ C. for thirty days, while others 

 were exposed to +3S" C. for 100 hours. Gravid females were obtained 

 from Morelos, Mex.; Los Angeles, Cal., and several more through the 

 kindness of Dr. R. E. Kunze, who took them at Phcenix, Ariz. The 

 female from Morelos deposited only a limited number of eggs by October 

 26th, which hatched November 5th, producing the form proxi?na, Guerin, 

 in December. The eggs from Los Angeles were obtained the latter part 

 of April, the imagoes appeared the beginning of June, all the males being 

 of the form autholea, Bdv. 



The eggs of two females taken by Dr. Kunze' at electric light, com- 

 menced to hatch October 18th. The larvae were fed during winter on 

 Cichorin»i endivia and Laduca sativa, var. Romana (Cos lettuce), this 

 diet being varied sometimes by winter-spinach. The rearing of the 

 progenies had, of course, to be accomplished at the regular temperature of 

 a dwelling room. 



The larvje grew rapidly ; November 16th the first pupse were obtain- 

 ed, all others finishing their larval state by December rst ; the majority of 

 moths appeared from December 3rd to 15th. 



Three successive inbred generations were then reared. Another 

 gravid female taken at Phoenix, April i8th, arrived at New York April 

 24th ; the eggs hatched April 28th, and the final metamorphosis took 

 place from June 4th to 15th. 



*Parts I., II. and III. appeared in the Journal N. Y. Entoni. Soc, Vol, X, 



