200 ON THE NATURAL HISTORY OF THE LAC INSECT. 



on to the bark of the branch, it soon becomes stationary, and enlarging as 

 the resinous secretion exudes from the surface of the body so as to surround 

 all parts except the oral orifice and the three apertures from which the 

 three white tufts issue, at the expiration of a month (that is, by the middle 

 of August) it measures in length almost the eighteenth part of an inch. If 

 we now examine it minutely, it will be observed that the legs, antennas, 

 and the whole of the chitinous parts of the body have become almost 

 undistinguishably incorporated with the resinous secretion, which, when 

 dissolved from the insect by spirit of wine, leaves the body almost 

 in a larval or caterpillar form, but without eyes or any other appen- 

 dages, save the three white tufts of hair-like filaments, and the 

 proboscis, which is now fully developed. The proboscis consists 

 of a fleshy projection, situated at a little distance from the head, 

 ventrally, presenting a depression in the centre, from which issue four long 

 hairs of setae, based internally upon as many pyramidal inflations, situated 

 almost at right angles to each other, and supported by other horny elements, 

 which also appear to belong to the machinery of the proboscis. These 

 hairs together form the penetrating organ through which the juice of the 

 tree is extracted ; but whether they are hollow, and do this individually, or 

 form a single tube by combination for this purpose, I have not been able to 

 determine. On the other hand, the three apertures from which the white 

 tufts proceed, and which are now seen to open through the incrustation, 

 are observed to be situated in the thorax and at the tail respectively — thus 

 identifying the latter, which still presents the circle of hairs round the anal 

 orifice, with the large papilla or anal orifice of the full-grown insect, and 

 the former or thoracic apertures with the two other papillae, which appear 

 to replace the wings. The white projecting from these we have already 

 seen to consist of the extremities of the tracheae, covered with a white 

 powder. Thus we see that the increase of size, which takes place in the female 

 insect, from its locomotive form to its idtimate development in the fixed 

 state, is chiefly effected by an enlargement and elongation of the body 

 between the mouth, on the one hand, and the parts from which the three 

 white tufts project, on the other ; for the oral extremity simply becomes 

 elongated, and the three other openings of the body remain as near 

 together, in the resinous incrustation, at the end as they were at the 

 commencement. Of what the white powder on the tracheae consists, I am 

 ignorant, further than that it does not dissolve in spirits of wine like the 

 lac, which, on the other hand, appears to be a secretion from the skin 

 generally, analagous to the chitinous one which would be required under 

 other circumstances. 



Male Insect. — On the 8th of September I visited the custard-apple tree 

 again, to see how the incrusted young were progressing ; and on close 

 examination of the parts where they were most congregated, observed, here 

 and there, little red insects actively crawling over them, which insects 

 appeared so like the original young ones, that I thought they must be a 

 few stragglers of a later evolution ; but on inspecting them more particu- 



