808 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



The j)ia<fs are short and irregular; there are two with distal extremities fringed 

 between the median lobes : two similar to these between first and second lobe of each 

 side; the lateral member of this pair of plates is much wider than the mesal one; 

 between the second and third lobes are usually four plates, each with its lateral mar- 

 gin fringed ; between the third lobe and the lobe on the lateral margin of the seg- 

 ment are four or five plates similar in form to those between the second and third 

 lobes; two of these plates are usually very small. The segment is narrowed caudad 

 by a succession of notches. 



151. The Norfolk-Island-Pine Coccus. 



Bhizococcus arattcariw (Maskell).* 



(Plate XXIX, Figs. 1, la— 1^). 



"The genus Rhisococctis was erected by Signoret to receive an insect 

 {B. gnidii) which he found on the roots of Daphne gnidium, and which 

 differs, according to his description, from the species of Eriococcus in 

 no important anatomical character, except in the antennse of the female 

 being 7-jointed. The specimens (female only) which Signoret studied 

 were naked ; but he had not sufficient material to ascertain if the 

 insect makes a sac or not in its most advanced stage. 



"During the past year I have studied two bark-lice which agree with 

 the characters given for Eriococcus^ except that the females have 7- 

 jointed antennte, and remained naked until they are fully grown. These 

 species I place provisionally in the genus Rhizococcus, and submit the 

 following characters, drawn from the species described here, for that 

 genus. 



Antenna} of larva and of the adult female 7-jointed ; ano-genital ring with eight 

 hairs; tarsi of both male and female each with four digitales ; margin of body of 

 young and of female in all stages fringed with tubular spinnerets, which are covered 

 with a waxy excretion ; adult male with single ocellus behind each eye, and a pair 

 of bristles on each side of penultimate abdominal segment, each pair supporting a 

 long white filament excreted by numerous pores at its base. The fully developed 

 female makes a dense sac of waxy matter within which the eggs are laid and the 

 shriveled body of the insect remains ; the full-grown male larva makes a similar sac 

 within which it undergoes its metamorphoses. 



'* During the summer of 1880, I found very common on the Norfolk 

 Island pine {Araucaria excelsior)^ growing in open air in southern Cali- 

 fornia, a bark-louse, which is probably the species that was described 

 in New Zealand by Mr. Maskell the year previous under the above 

 name. 



'' When a tree is badly infested with this pestit becomes blackened with 

 a black fungus, which I presume is Ftiniago salicina, which accompanies 

 coccids on orange and other trees. This is often the 13rst indication of 

 the presence of the insect which is observed. But when an infested tree 

 is carefully examined, numerous white, cocoon-like sacs containing the 

 full-grown insects may be seen closelj' applied to the sides or bases of 

 the leaves. Frequently these sacs are so massed at the ends of the 



* Eriococcus araucariw Maskell. Transactions and Proceedings of the New Zealand 

 Institute, vol. xi, p. 2lii. 



