ON THE NATURAL HISTORY OF THE LAC INSECT. 199 



liver consists of a single straight sacculated tube, of the same size through- 

 out, presenting a yellow colour, and giving off the hepatic duct a little 

 nearer one end than the other, while the trachea? are amassed into bundles, 

 apparently without order, and send forth many of their extremities through 

 the two small, as well as through the large anal apertures to terminate on 

 the surface of the lac in the way above mentioned. Lastly, we come to 

 the ovary, which consists of a voluminous tree of tubes, apparently branched 

 dichotomously, with each branch, large and small, bearing long elliptical 

 pouches, in each of which, again, is a correspondingly shaped ovum — the 

 whole nearly filling the body, and terminating in a single oviduct, which 

 opens (probably through the rectum) at the anal aperture. The ovum, on 

 the other hand, consists of an elliptical transparent envelope filled with 

 little cells, each of which contains oil (?) globules, and globules filled with 

 the red colouring matter. The oil-globules are spherical, uniform in size, 

 and much larger than the red globules, which are also spherical, but 

 distinctly separated from the oil-globules and from each other. Whether 

 these bodies respectively have delicate cell- walls or not, I am ignorant ; but, 

 while they are both distinctly defined in the ovum when the insect is first 

 opened under water, both soon burst by imbibition, and become lost to 

 view by dispersion of their contents. Thus, the red colouring matter 

 exists originally in the form of distinct globules, or in cells in the ovum. 

 The further changes in the ovum, preparatory to the full development of 

 the embryo, I have not followed ; but about the beginning of July the 

 young ones are perfectly formed, and, issuing through the anal aperture in 

 the incrustation, they creep on to the neighbouring parts of the branch, 

 and, soon fixing themselves by inserting their beaks into the bark, as before 

 stated, commence secreting the lac or resinous substance, in which they 

 soon become incarcerated. Myriads issue in this way, as may well be 

 conceived, when, at a guess, I should think, each insect contained a 

 thousand ; but by far the greater number die ; for, although the branches 

 become quite red with them, it is only here and there that a few, scattered 

 or in groups, live ; the rest still remain attached to the bark, but dried up 

 and dead, which may arise, perhaps, from not having been sufficiently 

 developed, or not being strong enough at their delivery to pierce the bark 

 for sustenance. On leaving the parent the young coccus is of a minium-red 

 colour, about one-fourtieth of an inch long, elliptical, obtuse anteriorly, 

 without any division between the head and body, possessing six legs, two 

 antennae, two small eyes, marginal and lateral, and two long hairs, growing 

 from the penultimate segment of the abdomen ; the body segmented 

 regularly ; the oral aperture ventral, and placed at some distance from the 

 anterior extremity ; two tufts of white, powdery, hair-like filaments 

 budding from the sides of the thorax respectively, in the place of wings, 

 and a tuft of the same kind, bifurcated, and curling outwards on each side, 

 projecting from the anal orifice. Anal orifice surrounded by a row of 

 short, strong hairs. At this period the insect is almost too small for 

 examination organologically ; but after it has crept off the incrustation and 



