Tachai'diincE. 409 



or bluntly pointed radiating processes, of which there are six superimposed 

 pairs on each side. These tests contain nymphs and the earliest adult females. 

 The median dorsal area is occupied by a ridge, with indications of segmentation, 

 which represents the larval exuvi;^. It terminates behind in an oval 

 operculum covering the anal aperture. The small stigmatic apertures open, 

 one on each side, near the anterior extremity of the median ridge. There are 

 usually three or more small bead- like protuberances on each side of the disc. 

 Subsequently, by a process of accretion, the irregularities are filled in, and the 

 test assumes a subglobular form, the surface of which is studded with more 

 or less concentric series of small rounded pustules which possibly represent 

 the apices of the earlier processes. In this stage the median dorsal area is 

 somewhat depressed. Further accretions of lac obliterate all trace of the 

 earlier characters, and the individuality of the tests is merged into the general 

 mass. In weak colonies the incrustation is thinner and not so continuous, 

 under which conditions the globular form of some of the tests may be retained. 

 A section of the incrustation (see upper end of fig. i) reveals numerous 

 pyriform or fusiform cells which are adapted to the form of the mature insect. 

 Each cell communicates with the exterior surface by the usual three 

 orifices which (in fresh, living material) are marked by tufts of slender white 

 filaments. 



Male puparium small ; the form usually obscured by the coalescence of 

 numerous individuals ; an isolated example (see fig. 12) may be described as 

 roughly coffin-shaped, with the posterior extremity covered by a large oval 

 operculum. The covering of lac is of sufficient thickness only to render the 

 puparium hard and rigid. Length approximately 2 mm. 



Adult female of a rich dark crimson colour, becoming blackish after death. 

 It attains the adult characters (recognised by the presence of the dorsal spine) 

 while still quite small (see fig. 10) ; but the stigmatic processes are then 

 practically sessile. At this period the insect rests in the normal position, with 

 the venter in apposition to the floor of the cell. The body, viewed from above 

 (see fig. 14), has a broadly rounded lobe in front and rounded tumescent 

 sides ; the dorsal spine occupying a median position between the stigmatic 

 and caudal processes, the latter process being recurved over the dorsum. 

 During subsequent growth the body first assumes a subglobular form and, 

 later, becomes greatly extended in an upward direction, until it attains a 

 pyriform {fig. 9) or fusiform {fig. 2) contour, with a corresponding increase in 

 the length of the stigmatic processes. In this later condition the caudal pro- 

 cess, with the dorsal spine and the two stigmatic processes, are clustered at 

 the upper extremity, while the lower extremity is occupied by the mouth parts. 

 After oviposition the ventral side of the insect, which has now assumed an 

 erect position, becomes slightly concave. The length and shape of the 

 stigmatic processes, in this species, have such a wide range of variation that 

 forms at opposite extremes might almost be accepted as distinct species. 

 They may be either comparatively short and stout, or long and proportionately 

 slender, with all intermediate degrees ; but the structure of the apical ceriferous 

 tracts, and all other essential characters, are identical in all the forms. The 

 truncate apex of the stigmatic process is occupied by a densely chitinous 

 area {fig. 5) in the centre of which is a shallow depression (the ceriferous tract) 

 with a sharply defined but irregularly lobate contour. This depression is 

 closely packed with small circular pores and exhibits — irregularly disposed 



3H 



