recapitulaloru aUiludes in Lepidoplera. 343 



in the drying (butterfly) attitude only twelve minutes, and 

 were then placed in the Geonietrid (deltoid) position. Being 

 disturbed some five minutes later, so that it ran two inches, 

 it settled again in the same attitude. The two costae form 

 an angle of about 100°; an hour later it was about 150°, 

 and in another hour the usual resting position was attained, 

 with costal angle of 190° to 200°, i. e. with the wings forward 

 of having the costae in line. 



Selenia illustraria. This species differs a good deal from 

 S. iUunaria in its methods of proceeding from wing expan- 

 sion to the normal resting position. Though in a warm 

 room, specimens would occasionally be more than half 

 an hour after emergence before any sign of the wings 

 expajiding could be detected. The wings then expanded 

 rather rapidly, taking, however, usually about or a little 

 over thirty-five minutes to expand. When expansion is 

 completed the wings hang backwards, but only the tips of 

 the fore-wings touch each other, not indeed always doing 

 so. Then gradually the wings approximate to the butter- 

 fly attitude, that is, closely pressed together dorsally, so 

 that the costae are coincident for their distal halves. 



The moth selects a vertical or, if possible, a sUghtly 

 overhanging position in which to expand, so that now they 

 hang downwards, more or less, whilst in this backward 

 position. A special feature is that this dorsal position is 

 gradually attained by quite imperceptible movement, and 

 this peculiarity continues throughout the whole evolution 

 from the beginning of expansion to the attainment of the 

 normal resting position ; there is no sudden movement as 

 is so common, either of throwing the wings back, or assum- 

 ing the resting position. This closing backwards is attained 

 in ten or fifteen minutes after expansion is completed ; the 

 wings are kept so for about twenty minutes and then are 

 gradually separated in a minute or two till the costa of 

 fore-wings are separated to an angle of 10° or 15°; the 

 separating movement is continued in the same gradual, 

 hardly noticeable manner, till in about two more minutes 

 the angle is 60°, in two more 90°, and in two or three more 

 finally 100° or 110°. Usually the process is rather slower, 

 and varies a good deal in its rapidity at different stages. 

 In the position of the moth, gravity no doubt tends to 

 make the wings hang directly backwards ; nevertheless, the 

 position of the wings at this stage is with the costae of 

 the anterior wings at an anole with each other of about 



