THE SILKWORM ITS FORM AND LIFE HISTORY. 31 



layer may be separated from the underlying coloured parts, and 

 then, when properly mounted, looks something like a piece of 

 network, with the six-sided meshes all accurately formed, and 

 covering the whole area. 



Such, in very brief outline, is the nature of the eye of the silk- 

 worm moth. We see that the convexity of form and the prominent 

 position of these eyes are advantages which counterbalance the 

 disadvantage of their immobility. Though the insect cannot 

 move its eyes, yet it can receive light from many directions at 

 once, in consequence of the peculiar form and position of those 

 organs, and it is, no doubt, able to see far better now than when 

 it was a caterpillar. 



The area between the eyes is densely covered with beautiful 

 cream-coloured hairs, brushed down, so to speak, over the 

 forehead. 



The head of a moth usually carries various mouth organs, but 

 that is not the case with our silkworm moth. This poor creature 

 has no apparatus for taking food ; it could not eat or drink if 

 it were to try, and, as a consequence, it endures a perpetual fast, 

 not only while a pupa, but in the perfect state as well ; its last 

 meal, like its first, is always taken w r hen it is a caterpillar, and 

 though it lives for nearly a month after beginning to spin its 

 cocoon it takes no more food, but carries on its vital processes 

 at the expense of the stores of nutriment laid up in its body 

 during its larval life. 



The thorax may be regarded as the central mass of the whole 

 organism, for to it are attached the head in front, the abdomen 

 behind, the wings at the sides, the legs beneath. The prothorax, 

 when denuded of hairs, appears on the upper surface as a narrow 

 plate. The long, creamy hairs attached to it stand almost erect, 

 forming round the neck above a sort of Elizabethan frill ; by a 

 parting in the middle they are divided into two sets, sloping in 

 opposite directions. They can be easily distinguished from the 

 rest of the thorax, and indeed are often mistaken for a part of 

 the head. Below, this segment is much more largely developed, 

 as it there carries the fore-legs. The mesothorax, which occupies 

 the greater part of the upper surface of the thorax, carries at its 

 sides two creamy tufts or lappets of hairs, which are pretty easily 

 distinguishable from those that cover the central part, and serve 

 to conceal the points of attachment of the wings. 



The legs are all six pretty much alike. Each consists of five 

 parts, only four of which, however, can be easily identified. First 

 there is a short cylindrical piece called the coxa or hip ; this is 

 jointed to a hole in the horny covering of the thorax beneath, 



