HEREDITY EXPERIMENTS WITH JUNONIA COENIA 



By Wilhelm Schrader, Los Angeles. 



On July 5th. 1911, we caught a fertile female of Junonia 

 coenia (Hiibner) in Los Angeles, which to all general appear- 

 ances had the same color and markings as our usual form ; 

 from this specimen were obtained some eggs and 100 cater- 

 pillars were raised in the normal summer temperature; and 

 31 caterpillars were raised in the incubator where the humid- 

 ity was very dense, and varied between 70° and 90° F., and 

 the temperature was 80° to 90° F. The caterpillars in such 

 a dense humidity and high temperature need the very best ol 

 care, because such conditions easily produce the so-called 

 "wilt" disease ; caterpillars thus affected grow mostly to their 

 full size, then become soft and die in about two days, hanging 

 usually by their middle legs, sideways, on the food-plant or 

 walls of the cage. Even the chrysalids will get this disease 

 and turn dark and die. 



This disease is contageous and often appears in the next 

 generation of the caterpillars, even after the greatest care and 

 isolation ; the best remedy seems to be to place such affected 

 stock in cool air, and clean the cage often, separating all 

 caterpillars which feel soft, from the others. 



In our other experiments with Junonia bred in the same 

 temperature and humidity, the parents of which were also 

 caught in Los Angeles, from which we have now at the time 

 of this writing, the 35th generation by inbreeding, the ocelli 

 of the forewings evolved an appendix beneath ; this change 

 in the marking appeared already in a few in the second 

 generation, beginning as a little separate point as described 

 in the Pomona College Journal of Entomology, Vol. V., Nos. 

 1, 3, and increased in size and percentage in each following 

 generation, by inbreeding and raising in the same tempera- 

 ture and humidity. 



Now, from this newly caught fertile female, the descend- 

 ants from which were 31 caterpillars in this part of the experi- 

 ment, bred in the same temperature and humidity, the ocelli 

 of the hindwings became, in the first generation considerably 

 reduced in size ; while the size of the butterfly, on the average, 

 increased in wing expansion very considerably over that of 

 the rather large mother; even the males, which are usually 

 smaller than the females, were larger than this female ; the 

 ground color of all these butterflies was darker; the two 

 orange-colored spots of the forewings, near the costal margin, 

 were larger than is usual in our local form. All Junonia bred 

 in a hot temperature and humidity become somewhat darker, 

 however, not so dark as this new line ; the forewing showed 

 another new development, as seen in the direction that the 



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