Insects' Eggs. 327 



the green granules, which are only mitrate oil globules. When, 

 however, the egg arrives at maturity, and the upper chamber 

 has been removed by absorption, these green granules will be 

 found to be replaced by dark green globules, regular in size, 

 and about 1 -8000th of an inch in diameter, and which appear to 

 be in no way the same in the yolk of Phryganea eggs." 

 Another curious fact has been noticed, which partially bears on 

 the question of colour, the production of parasitic bodies 

 within the eggs of some insects. In the Coccus, for instance, 

 parasitic cells of a green colour occur, shaped like a string of 

 sausages, in length about thel-2000th of an inch, by about the 

 l-7000fch of an inch in breadth. Of the formative process and 

 composition of the colouring matter, not much is known. Va- 

 lenciennes and Framy, after having bestowed attention on this 

 part of the investigation, selecting the ova of Crustaceans for 

 their purpose, arrived at the conclusion ' ' that it is the same as 

 that existing in the shell; which being green in the moist 

 state, passes into a red colour when solidified." By the aid of 

 alcohol, etc., the colouring matter can be separated and collected 

 in sufficient quantities for spectrum examination. The eggs of 

 moths and butterflies, as I have before stated, present many 

 varying tints of colour, and in speaking of this quality I do not 

 restrict the term solely to the prismatic changes to which allu- 

 sion has been made, and which are liable to constant mutations, 

 according to the accident of the rays of light thrown upon 

 them, but I more particularly refer to the several natural tran- 

 sitions of colour, the prevailing tints of which are yellow, 

 white, grey, and a light brown. In some eggs the yellow, 

 white, and grey are delicately blended; and these, when viewed 

 with a magnifying power of about fifty diameters, and by the 

 aid of a side-reflector (parabolic reflector), present many beau- 

 tiful combinations, and the most delicate opalescent, or rather 

 iridescent tints appear on others. The egg of the Mottled- 

 umber moth (Erannis defoliaria), Fig. 8, is in every particular 

 very beautiful. It is ovoid, with regular hexagonal reticula- 

 tions, each corner is studded with a white raised knob or 

 button ; the space within the hexagon is finely punctuated, 

 and the play of colours is exquisitely delicate. In this egg I 

 have been unable to make out a micropyle. The Magpie moth 

 {Abraxas grossularia) , Fig. 1, is another example. The egg 

 is ovoid, and somewhat resembles the former, but does not pos- 

 sess the raised stud or button, at the corner of each hexagon ; 

 its colour is very delicate, and silvery in tone. The membrane is 

 so translucent that the movements of the young worm can be 

 very well seen within. The egg of the Thorn moth (Ennomos 

 erosaria), Fig. 5, is an elongated square form, one end of which 

 is slightly tapered off, while the other is flattened; in this 



