40 Mr. P. Merrifield on the effects of artificial 



while freshly pupated, I believe temperature applied 

 early in the larval stage has effected a complete con- 

 version as regards habits, but I do not know whether it 

 has had this effect on the colouring. 



C. caja. — Dr. Chapman kindly sent me, at the begin- 

 ning of February last, a batch of eggs which had been 

 laid by a female in captivity. These I forced, and had 

 from them more than 100 pupae between the 12th and 

 24th March. Some of these were forced at 80°, some 

 placed in the refrigerator at about 47°, a few more at 33°, 

 and others at a temperature varying from about 50° to 60°. 

 Those at 33° died after a time, those at 47° either died 

 or emerged in a ver}^ crippled condition, many of those 

 at 50° to 60° died, but of those at 80°, about 30, nearly 

 all emerged, with no cripples. Unfortunately all but 

 one of these last-named were males, while most of the 

 others which emerged were females ; so that the means 

 of comparison are not so exact as might have been 

 desired. Still, they show unquestionable differences 

 corresponding with their treatment. In the fore wings 

 of those forced the brown ground colour is paler, the 

 colouring of the hind wings is a yellower orange, and 

 their dark spots are smaller, and show a less tendency 

 to coalesce. But the most striking feature is in the 

 black bars across the abdominal segments ; these, with 

 scarcely an exception, are much longer and broader in 

 the moths from the pups kept at the lower temperature 

 than in those from the higher temperature. I exhibit 

 three average samples of the forced males and the one 

 forced female, and two males and two females of those 

 at the lower temperature — average examples. 



These experiments having indicated that caja flourishes 

 under a high temperature, I placed some more pupae, 

 afterwards kindly sent me by Dr. Chapman, at the 

 temperature of 80° — 90° ; the effect was to increase 

 sensibly the pallor of the brown part of the fore wings, 

 especially towards the outer margin, where the colouring 

 assumes a clouded and blotchy appearance. I had five 

 of these, and exhibit two of them, typical specimens, or 

 only slightly paler than the average of the five. 



Size and shape as affected by temperature in the pupal 

 stage. — This is a subject I approach with some hesitation, 

 because accidental circumstances have interfered with 

 the completion of the crucial tests I meant to have 



