MasxeLL.—On New Zealand Coccide. 187 
rather less than half as long as the tibia: the four digitules are fine 
hairs. The usual hairs and spine on the tibia, and two spines on the 
lower edge of the tarsus, not far from the claw. There are three pairs of 
eyes. The abdominal spike is short and thick, and exhibits a curved 
appendage similar to, but rather longer than, that of Acanthococcus 
multispinus, mihi (Trans., vol. xi., pl. viii., fig. 187). This appendage is, 
indeed, common to the three genera Eriococcus, Acanthococcus, and Rhizococ- 
cus. At the base of the spike are two rather strong sete, one on each side. 
Rhizococcus fossor does not construct a cottony sac (for the female), but, 
instead, buries itself usually in a circular hole or pit, in the leaf it lives on. 
Many adult insects may be found simply resting on the leaf, accompanied 
by a number of young larve and females in the second stage. But in most 
cases they pass their last stage in a pit. The young insect is very active : 
the female of the second stage moves about sluggishly ; in the last stage it 
is fixed and stationary. At first it appears simply to lie on the leaf (on the 
under-side), but in a short while, whether from some chemical action pro- 
duced by it or by mechanically compressing the cells of the plant, a circular 
elevation or wall on the leaf is raised up round the insect. At the same 
time the portion of the leaf beneath the body i is pressed downwards, and a 
corresponding elevation appears on the other side: this elevation assumes a 
brown tint. As the depression continues and the wall grows the insect 
sinks deeper in the leaf, becoming more and more buried, and the wall 
curls over it a little, so that in fact the orifice of the pit is somewhat 
smaller than the cavity below. The insect lies in the pit (which may 
average about 41 inch in diameter at the opening, and is circular) with the 
head downward, and the anal tubercles and pencil of white cotton appear- 
ing over the wall, I presume to attract the male. Afterwards, as gestation 
proceeds, the whole body disappears in the pit, where the young larve are 
born. These cavities in the leaf look like small volcanic craters, and the cor- 
responding brown elevation on the other side of the leaf is quite conspicuous. 
Sometimes two insects may be found in the same pit, one lying over the 
other. I suppose the upper one simply took advantage of a ready-made 
domicile. The insects which are not in pits are generally darker in colour 
than the others. 
On leaves of maire, Santalum cunninghamii, from the North Island, sent 
to me by C. P. Winkelmann, Esq., of Te Aute. 
This is an interesting and peculiar insect, certainly differing from any 
that I know of in the genus. The curious mode adopted by it of burrowing 
into the leaf is, I think, unique.  Ctenochiton viridis, mihi, produces a 
certain depression in the leaf it lives on, but by no means so complete a 
shelter for itself as does this little Rhizococcus. 
