340 Dr. T. A. Chapman's FiirlJier Notes on 



tlie wings being stiffer aiid holding themselves straighter. 

 About, this time the hind-wings tend to be a little separate 

 from the fore- wings when open. Then the fore-wings open 

 but little and the hind- wings rather more. Gradually by 

 about fourteenth opening the hind-wings only open, or the 

 fore-wings hardly perceptibly ; gradually the separation of 

 the hind-wings diminishes, and somewhere about the six- 

 teenth to twentieth alternation one may say the process 

 has finished. When closed, the wings at first close very 

 close up to the thorax, their limpness causing no resistance 

 by the further portion of the wings to this approximation ; 

 as the wings get stiffer they do not close so far up, only 

 sometimes for a third or half-way from the apex. Later, 

 when the final resting attitude is assumed, they close 

 further up, nearly as far as at the first closing. One or 

 two specimens opened more than the usual 8 or 1'2 mm., 

 one as much as 20 mm. and might fairly be described as 

 in the bell attitude. 



Throughout the process the butterfly at intervals, with- 

 out reference to the wings being opened or closed, makes 

 a shivering movement, at others rocks to and fro a little — 

 this more frequently on closing the wings, and more frequent 

 in later stages — and makes a few fluttering movements of 

 the wings of an amplitude of about 0'5 mm. All this time 

 the antennae are well separated, much as in the mature 

 butterfly, but are directed slightly behind a line at right 

 angles to the line of the body, which is reached by them 

 about the time the wings finally close, but do not reach the 

 final somewhat porrect position till an hour or more after; 

 their advance to this position is gradual and imperceptible. 

 The hind-wings have the costae nearly level with those of 

 the fore-wings when mature, during the opening and shut- 

 ting movements they are usually a millimetre or two behind. 



AVe have here, though less obvious, just as in P. rapae, 

 an effort to assume the Lepidopterous resting attitude, i. e. 

 with the wings flat, but as in P. rapae it occurs not after 

 the wings are dry but during their drying, being as it were 

 pushed backwards in the ontogeny. 



Pieris ■riapi. The process in napi is almost intermediate 

 between those of rapae and hrassicae, the bell attitude 

 results from the wings being depressed to an angle of about 

 45° (90" between the opposite wings) instead of the 90° of 

 rapae or the 15° or 20° of brassieae. The details differ a 

 little, but hardly to a degree worth full description. 



