STATES OF INSECTS. 77 



exposed in full day have usually an opaque and horny 

 texture. 



Some insects are spared all trouble in providing a 

 covering for their eggs, their own bodies furnishing one 

 in every respect adapted to this purpose. Not to mention 

 the Onisci, or wood-lice, since they rather belong to the 

 Crustacea, which have a four-valved cell under the breast, 

 in which they carry their eggs, as the kangaroo does its 

 young in its abdominal pouch, the whole body of the fe- 

 male of those strange animals the Cocci becomes a cover- 

 ing for her eggs, which it incloses on every side. To make 

 this intelligible to you, further explanation is necessary. 

 You must have noticed those singular immovable tortoise- 

 shaped insects, which are such pests to myrtles and other 

 greenhouse plants. These are the young of a species of 

 Coccus (C. Hesperidum L.), and their history is that of the 

 whole race. Part of them never become much bigger than 

 the size of which you ordinarily see them, and when full- 

 grown disclose minute two-winged flies, which are the 

 males. The size of the females, which glue themselves to 

 a twig or leaf as if lifeless, now augments prodigiously, 

 and the whole body, distended with the thousands of eggs 

 which it includes to the bigness of a large pea, without 

 any vestige of head or limb, resembles a vegetable ex- 

 crescence or gall-apple rather than an insect. If you 

 remove one of them, you will perceive that the under 

 part of its abdomen is flat and closely applied to the 

 surface of the branch on which it rests, only a thin 

 layer of a sort of cotton being interposed between them. 

 In laying her eggs the female Coccus does not, like most 

 insects, protrude them beyond her body into day-light ; 

 but as soon as the first egg has passed the orifice of her 



