Maskell. — On New Zealand Coccidse. 137 



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 

 muliispinus, mihi (Trans., vol. xi., pi. viii., fig. 18/). This appendage is, 

 indeed, common to the three genera Eriococcus, Acanthococcus, and Rhizococ- 

 cus. At the base of the spike are two rather strong setae, 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 larvas 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 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 Jg- 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 larvas 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. 



