SATURNIA PAVONIA. 327 



hedge about a foot from the top of the bank, on which the hedge 

 was growing, near Sudbury ■ while the hedge is in foliage the 

 cocoons must be very completely hidden, and, later, exposure to the 

 weather has so brought the colour into uniformity with those of the 

 surrounding branches that eyen when the hedge is leafless it is difficult 

 to detect them (Ransom). 



Cocoon. — The cocoon is flask- or pear-shaped ; the broad end 

 rounded and closed, the narrow end with a bottle-neck-shaped 

 opening for exit of moth ; composed of a loose fluffy silken outside 

 covering, into which pieces of leaves, dirt, etc., are spun. The 

 inner portion felted, deep red-brown in colour ; the inside surface 

 shining and smooth as if gummed. The peculiarity of the cocoon 

 is the remarkable ee'-trap arrangement, that, springing from the 

 shoulders inside the cocoon, makes an exit which, while it excludes 

 any external marauders, opens readily under the pressure of the 

 emerging insect from the inside. Albin was the first to notice the 

 peculiar exit made by the Saturniid larvae to their cocoons, but 

 Reaumur's description of the cocoons and of the mode of escape of 

 the imagines therefrom is quite unrivalled. He explains how, in spite 

 of the toughness of the silk, the moths on emergence have only to 

 push open a sort of fringe in order to escape. His detailed ob- 

 servations, after noting that the cocoons containing a living pupa 

 and one from which the imago has emerged are perfectly similar, 

 and the outlet for escape scarcely visible in the latter, read (JlJem., 

 L, p. 627) as follows: " Un des bouts de la coque (pi, xlvih., 

 fig. 4/; pi. xlix., fig. 3 ; pi. 1., fig. 2) est plus menu que l'autre, 

 et on y voit des poils qui ne sont pas couches comme ils le sont 

 ailleurs. Si on se contente de regarder grossierement ce bout de 

 la coque, on juge seulement que le fil n'y est pas devide, qu'il y 

 forme une masse cotonneuse, semblable a celles qui enveloppent 

 d'autres coques en entier ; mais si on regarde plus attentivement, 

 on observe que tous ces fils, qui ne sont pas adherants les uns 

 aux autres, se dirigent vers un meme point pour former une 

 espece d'entonnoir qui est le bout de la coque ; enfin le bout de 

 la coque est une espece d'entonnoir forme par les fils d'une frange. 

 La comparaison meme aux fils de frange est exacte, si on prend 

 une frange avant que ses fils ayent ete tors, ou en termes de 

 l'art guipes, alors chaque fil de la frange est compose d'un fil pile 

 en deux, c'est en tordant ces deux parties du fil qu'on les reunit ; 

 le bout de chacun des brins de soye qui se rendent a la pointe 

 de la coque, est fait aussi par un fil qui se replie sur lui-meme. 

 Nous avons deja dit que ces fils sont gros ; d'ailleurs, ils sont bien 

 gommes, leur ressort les tient tous dans la premiere direction qui 

 leur a ete donnee et les y ramene lorsque quelque force les en a 

 tires.". To emerge the imago advances freely in this funnel, it 

 finds no great trouble to widen the detached threads which form 

 the walls, and when it has emerged the elasticity of the silk 

 makes them return to their former situation, and it thus results 

 that a cocoon with a living pupa, and one from which the 

 imago has emerged, are externally similar. Reaumur then goes 

 on to show that not only does the construction of the cocoon allow 

 easy egress to the emerging imago, but also that it keeps out its 

 numerous enemies. He writes {loc. cit., p. 628) : " Outre l'entonnoir 



