a THE ENTOMOLOGIST. 
and with the regularity of a machine, of which, indeed, the sound 
very much reminded me. She laid, in the first week, stuck in 
groups and strings to the surfaces around, about one hundred 
and sixty eggs, barren, of course; but which agreed in size, form, 
and colour, with fertile eggs of the species, which I had just 
received from the same sources as the cocoons. 
EGG. 
The egg of Attacus Atlas (Plate, fig. a.) is not so large as that of 
Anth. Pernyi, and not nearly so large as that of Anth. Mylitta, being 
about 0-08 inch in length, broadly, but irregularly, ovate, granular on the 
surface,* white, clouded with purple-brown, which tint centres in an 
irregular mass of intense depth. All this colour is readily washed-off by a 
few moments’ immersion in water, the tinge being communicated to the 
water; leaving the whole surface of the egg of a delicate greenish-white. 
The darkest portion of the colour is now seen to reside in a knot of jelly- 
like membrane +, which, when softened by the immersion in water, can be 
drawn out to considerable length, but possesses great tenacity, and great 
elasticity, and adheres to the egg very firmly. 
Of fertile eggs I received a dozen from Mr. Watkins, which 
had been laid on the 23rd July, and a dozen from M. Wailly, laid 
* Examined with the Microscope (3 in. obj. Powell’s) by transmitted light, the 
appearance of the egg-shell is highly curious. The whole substance is semi-opake, 
studded equally everywhere with elliptic rings of light, separated by little more than 
their own area, and inclosing a space absolutely opake. Each ring is brighter at one 
side of the circumference than at the other, which suggested the thought that the 
light was reflected from a raised edge of a cavity. But a revolving of the stage 
under my eye, made no change of the illuminated side: and a shutting-off of the 
rays from the window that impinged on the stage did not diminish it. It was 
therefore transmitted light through the rings; it was the same whether the interior 
or exterior surface of the egg-shell were next the eye. I can suggest no other 
explanation of the appearance than this: the entire shell of the egg is perforated, 
nearly (not quite; for the light of the ring is not quite the light of the sky reflected 
from the stage-mirror, but evidently transmitted through a very thin medium), by a 
symmetrical series of ring-like cuts, within the area of which the shelly substance 
rises exteriorly into thickened knobs; whence the deeper opacity; and which 
produce the delicate granulation. It is probable that here is a provision for the 
supply of air to the unborn larva. But why should this species need such a provision 
more than others? In the large egg of Mylitta there is nothing like it. When this 
is examined under like conditions, there is an appearance of irregular pits all over 
the shell, but there is no transmitted light, no semblance of even approximate 
perforation. 
+ The alternately distended and collapsed egg-tube. (See Owen’s Comp. Anat. 
Invert. (1855) p. 401; fig. 158.) 
