58 DWIGHT E. MINNICH 



GENERAL METHODS 



The experiments were carried out chiefly during the month of 

 July. The laboratory was a basement room of northwest expo- 

 sure, but direct sunlight was kept out by white-cloth shades at 

 the west windows. Ventilation was accomplished entirely from 

 the interior of the buildng, so that it was possible to avoid sudden 

 and pronounced fluctuations of temperature. During the entire 

 period of experimentation the extremes of temperature registered 

 in the laboratory were 21°C. and 25.9°C. For the great majority 

 of days, however, the temperature ranged from 22° to 24°, the 

 variation for the day being less than 1°. Ventilation from the 

 inside of the building also insured a more uniform condition of 

 humidity than outside ventilation would have allowed. Every 

 precaution was thus taken to maintain as great constancy of the 

 general laboratory environment as possible. 



The specimens employed were all exceptionally large and 

 perfect. After hatching, they were housed in large cages (0.9m. 

 X 0.4m. X 0.4m.) consisting of a light wooden framework covered 

 with mosquito bar. Excepting periods of starvation, which were 

 practiced from time to time during experiments, the animals 

 remained in excellent condition. In one or two instances, near 

 the end of an experiment, one leg of a specimen became more or 

 less stiff and functionless as far as locomotion was concerned. 

 Also the wings, in addition to being clipped slightly for purposes 

 of indentification, became somewhat frayed and considerably 

 rubbed in their outer portions, due to the effects of the holder in 

 repeated trials. But as far as I was able to observe, these slight 

 mutilations in nowise affected the reactions which were being 

 studied. In general, the hairy proximal portions of the wings 

 and the rest of the body remained in almost perfect condition — ■ 

 much more so than is the case with animals in a state of nature. 

 Thus butterflies caught in the field frequently have lost por- 

 tions of the labial palpi, but of the eight animals in my experi- 

 ments not one suffered such a mutilation. 



Even in their most vigorous states, however, the butterflies 

 flew but little. It was not that they were unable to fly, but that 

 they merely did not. Neither did they creep much, usually 



