Proceedings. 41 



been proved that by means of artificial frigidity the develop- 

 ment of a chrysalis may be retarded for many years beyond 

 its proper time, just as heat would seem to exercise exactly 

 the opposite effect. 



After describing the emergence of the butterfly from the 

 pupa, Mr. Blaber said : — " If we examine an insect immedi- 

 ately it has left the pupa, we find that we are able to draw out 

 its wings to their normal size, so easily do they stretch, 

 thereby proving that all the proportions are as well-formed 

 as they ever will be, and only require expansion. Frequently 

 the insect during emergence ruptures one of its little veins, 

 the fluid therefrom escapes, and the result is a cripple with 

 crumpled wings. Generally within an hour the development 

 is complete, and the wings are ready for flight. 



" The emergence of moths from their cocoons is more 

 difficult. Some species, such as the Pass Moth (Dicranura 

 vinula), are provided with an acid secretion which they dis- 

 charge, and by its solvent power the wall of the cocoon soon 

 loses its cohesion, and gives way to the slightest pressure. 

 With some other species the means of egress is provided for 

 by the caterpillar, by leaving a small portion at one end to 

 act as a hinge. A much more elaborate contrivance is, how- 

 ever, resorted to in the case of the flask-shaped cocoon of the 

 Emperor Moth {^Satundd pavonia). It is generally of a soUd 

 tissue of layers of silk, almost of the texture of parchment, 

 but at the narrow end it is composed of a series of loosely- 

 attached threads couvei-ging, like so many bristles, to a blunt 

 point, in the middle of which is a circular opening. It is 

 through this opening that the moth emerges. The aperture 

 is a sort of reversed funnel formed of converging threads that 

 readily yield to pressure from within." 



Mr. Blaber described the organs of the perfect insect, and 

 mentioned that in Great Britam we can only muster sixty-six 

 different species of butterfly, whilst the moths number nearly 

 1900 species. Some of these are very local as to their 

 habitats, being very common in one particular spot, and ex- 

 tremely rare elsewhere. 



