156 ENTOMOLOGY 



into a balloon-shaped bag, were it not for hypodermal fibres which hold 

 the wing-membranes closely together (Mayer). Tropaa luna and 

 Philosamia cynthia cut and force an opening through the cocoon by 

 means of a pair of saw-like organs, one at the base of each front wing. 



The cocoons of Samia cecropia and Callosamia promethea do not 

 have a gummy coating over the entire interior. In each case the end 

 through which the moth emerges is composed of silken fibres loosely 

 pulled together and not covered with a gummy substance. It is as if 

 each layer of the cocoon was spun into a fringe at this end, the fringes 

 of all layers being bunched together forming a little cone. In the co- 

 coon of Samia cecropia, it is possible to push a pencil through this 

 fringe with apparently no effort. The fibres part readily, it being neces- 

 sary to break only a few in the extreme outside layer. The same can 

 be said of the cocoon of C. promethea (H. B. Weiss). 



The temperature inside a cocoon is practically the same as that of the 

 surrounding air, there being a constant tendency for the inside tem- 

 perature to approach that of its surroundings. Sudden changes of 

 temperature do not occur within a cocoon. When the outside tem- 

 perature is suddenly lowered, as from 10 C to o C., the temperature in 

 a cocoon falls gradually, and even during a gradual rise the cocoon- 

 temperature lags behind that of its surroundings, on account of the poor 

 conducting qualities of air and silk (H. B. Weiss). 



Hypermetamorphosis. In a few remarkable instances, metamor- 

 phosis involves more than three stages, owing to the existence of super- 

 numerary larval forms. This phenomenon of hyper metamorphosis 

 occurs notably in the coleopterous genera Meloe, Epicauta, Sitaris 

 and Rhipiphorus, in Strepsiptera and in several parasitic Hymenoptera. 



In the oil-beetle, Meloe, as described by Riley, the newly-hatched 

 larva (triungulin} is active and campodea-form. It climbs upon a 

 flower and thence upon the body of a bee (Anthophora), which carries 

 it to the nest, where it eats the egg of the bee. After a molt, the larva 

 though still six-legged, has become cylindrical, fleshy and less active, 

 resembling a lamellicorn larva; it now appropriates the honey of the bee. 

 With plenty of rich food at hand the rarva becomes sluggish, and after 

 another molt appears as a pseudo-pupa, with functionless mouth 

 parts and atrophied legs. From this pseudo-pupa emerges a third 

 larval form, of the pure eruciform type, fat and apodous like the bee- 

 larvae themselves. After these four distinct stages the larva becomes 

 a pupa and then a beetle. 



Epicauta, another meloid, has a similar history. The triungulin 



