52 STRUCTURE OF THE LEPIDOPTERA 



chrysalides of Populi [the Poplar Hawk Moth, page 209] which, 

 from the looseness of their cases, were thought to be just on the 

 point of emerging. At 8.46 one of them showed signs of restless- 

 ness ; and, after a few vigorous movements, during which it rolled 

 itself over on the glass [I had placed the pupae on a piece of plate 

 glass so that slight movements might be more easily detected], the 

 front of its case was suddenly thrust off with considerable force ; 

 and in less than four seconds the imago was quite free and 

 crawling on the table. After trying hard to reach a higher point 

 than was provided for about four minutes, it rested to expand its 

 wings now about seven- sixteenths of an inch long, or one-third 

 the total length of the body. At 9 o'clock the wings reached 

 half the length of the body, and were much curled. At 9.12 they 

 were fully expanded and straightened out.' 



From this extract we see that the whole period from the 

 bursting of the case to the full expansion of the wings was only 

 twenty- six minutes ; and it will be well to remind the reader that 

 the process occupies even a much shorter time than this with 

 many species, both of butterflies and moths. It will be observed, 

 also, that the evening was chosen as the time for the observation. 

 There was a reason for this. The Poplar Hawk Moth, as is the case 

 with many others, almost invariably emerges from the chrysalis in 

 the evening usually after dark. But it may be mentioned in 

 passing that a far larger number of the Lepidoptera as invariably 

 emerge in the morning. 



Again we will return to our newly emerged insect, for there are 

 still one or two interesting points to observe. The wings have 

 fully expanded, it is true, but how very limp they are ! Take the 

 creature on the tip of your ringer and hold it so that its body is 

 in a horizontal position. Immediately the wings bend downward 

 with their own weight, so soft and flexible are they. The body, too, 

 is still very soft, and apparently much too heavy for flight. Then, 

 if you place it on a flat surface, it will immediately try to find 

 some perpendicular or overhanging surface from which it can 

 suspend itself by means of its legs, so that the pendant and 

 straightened wings are in the best possible position for drying. As 

 the insect walks away in search of such a resting place, the body 

 still drags as it did before, and the wings bend over, either both on 

 one side or one on each side of the body. 



It is some time before the wings are sufficiently dry and rigid 

 for flight, but the period varies greatly with different species, 



