Tachardiince. 403 



in apposition with the caudal extension and anal orifice. During 

 the life of the insect these apertures are occupied by tufts of 

 delicate white filaments emanating from ceriferous pores on the 

 organs concerned. The deposition of lac commences during the 

 larval stage, and is continued — increasing in thickness with the 

 development of the insect — throughout the nymphal and adult 

 stages. 



As the insects, while still quite small, are closely imprisoned 

 within a rigid case of resin, it is evident that their growth must be 

 accompanied by a corresponding augmentation of the internal 

 dimensions of the cell. The final size of the adult female is many 

 times greater than that of the nymph or of the early adult female, 

 necessitating a great increase in the size of the cavity. It is a little 

 difficult to understand how this is effected. The probable explana- 

 tion is that the resinous secretion, though apparently a solid 

 substance, is, in reality, a viscous fluid which would respond to 

 slow pressure exerted by the growth of the contained insect. We 

 know that a very small amount of heat will make a stick of sealing- 

 wax (which is derived from lac) sufficiently plastic for it to bend 

 by its own weight or to adapt itself to the shape of any surface 

 upon which it may be resting. Possibly the heat of the tropical 

 sun comes to the assistance of the imprisoned insect by inducing 

 the necessary plasticity in its resinous envelope. 



The male puparium is similarly constructed, but is usually of a 

 more or less slipper-shaped form, with the posterior aperture pro- 

 portionately larger and closed by a dense resinous operculum. 



The form of the female insect itself varies with each species and 

 is affected — to a considerable extent — by contiguity, and by the 

 depth of the resinous deposit. In T. lacca, where the lac may 

 attain a thickness of seven millimetres or more, the insect is 

 correspondingly elongated, assuming an irregularly fusiform shape, 

 the mouth parts alone being in contact with the plant. Other 

 species are subglobular or even somewhat depressed, while others 

 have a symmetrical lobate form. 



The antennae are usually very rudimentary, consisting merely 

 of more of less pronounced tubercles surmounted by a few bristles * 

 in conchiferata they are rather more developed, exhibiting four 

 distinct joints, while in minuta, though they are elongated, no 

 definite segmentation can be distinguished. 



The mouth parts are of the usual structure, but are associated 

 with a pair of small but prominent post-oral lobes (situated imme- 

 diately behind the mouth), the function of which is not clear. They 



