234 Transactions. — Zoology. 



tomical characters, and probably the modes of growth on the 

 leaves or under the bark may differ to that extent. 



On account of this difference it is necessary to be rather 

 more precise than I was in 1891 in detailing the organic cha- 

 racters of this species. The most important of these is the 

 anogenital ring, which departs entirely from the type of 

 Dactylopiiis, having more than six (usually twenty) hairs. 

 This character, as far as experience goes at present, is suffi- 

 cient to determine the species at once. With regard to the 

 mentum, I was in doubt last year whether it is monomerous 

 or not : further examination leads me to think it is not, and it 

 would therefore not be exceptional ; but certainty as to the 

 mentum is by no means easy. The antenna has seven joints, 

 as mentioned in 1891 ; it may be recognised by two very long 

 hairs, one on the first and the other on the second joint (with, 

 of course, other shorter hairs). The four digitules are all much 

 longer than the claw. 



I shall still leave this species in Dactylopius, in spite of 

 the exceptional anal ring. Perhaps some day somebody may 

 find out how it constructs the pit on the leaf in which it 

 lives. 



Genus Pseudococcus, Westwood. 



Pseudococcus nivalis, sp. nov. Plate XVI., figs. 1-4. 



Adult female covered with a quantity of white cotton, and 

 excreting also a white cottony ovisac of less dense texture 

 than that on the dorsum. This ovisac is frequently pro- 

 longed posteriorly as in the Lecanid genus Pulvinaria. In- 

 sect yellowish - brown, elliptical, slightly convex ; length 

 about jVin. Antennae of nine joints, the first short, the 

 second the longest, the rest gradually diminishing to the 

 eighth, the last as long as the fourth ; the fourth, fifth, and 

 sixth are more slender than the others. Feet rather long and 

 slender ; tarsal digitules fine hairs ; there are no digitules on 

 the claw. Anal tubercles very minute and inconspicuous, 

 setiferous ; the anogenital ring has six hairs. Margin bearing 

 on each segment a group at each side of large circular spin- 

 nerets, and these are also numerously scattered on the dorsal 

 abdominal region. On the cephalic region are groups of conical 

 spines. 



Female of the second stage, and larva, not observed. 



Adult male dark-yellow or orange ; length about ^in. 

 Antennas of ten joints, diminishing gradually from the third to 

 the tenth. Abdominal spike short ; there are two very long 

 " tails " and two shorter median setae. Dorsal eyes two, 

 ventral eyes two, ocelli two. 



Hab. In Australia, on Acacia sp. My specimens are from 

 Mr. Koebele ; the locality either Sydney or Brisbane. 





