92 Transactions. — Zoology. 



take rank only as one of the many varieties which may be 

 attached to D. adoniduvi. 



Subdivision IDIOCOCCIN^. 



Genus Sph^rococcus. 



SphserococGUS leptospermi, sp. nov. Plate VI., figs. 4-14, 



Insects inhabiting woody galls, which are merely swellings 

 of the twigs of the plant. These galls vary in size (in the 

 specimens seen) from -Jin. to lin. in length, and from ^in. to 

 l^in. in thickness, apparently according to the size of the twig 

 they are on. In young unharmed specimens the gall, though 

 rough like the tree-bark, is usually closed and firm all round, 

 but when old or parasitised there is a longitudinal slit on one 

 side, and the adjacent parts of the gall are soft and rotten. 

 Frequently one of these old galls will have in it many large 

 parasitic (seemingly dipterous) grubs. In a few cases I have 

 found two adult female Coccids inhabiting the same gall. 



The interior of the gall is smooth, with a layer of white 

 cotton, which is usually very thin, but which in some speci- 

 mens becomes rather thick, and forms a sort of cushion for the 

 insect. The larvae congregate round the mother and fill the 

 gall. 



The adult female fills the gall, and is as a rule of a dark 

 greenish-grey colour, which becomes dark-brown and almost 

 black wdth age. The general form is elliptical; the length 

 a,verages about Jin., but varies a good deal. The antennae are 

 obsolete, but appear to be represented by very minute tu- 

 bercles, which, however, I have only been able to detect on 

 insects before gestation ; in the latest stages I cannot make 

 them out. The feet are entirely absent. The rostrum, which 

 is rather large, is situated almost in the middle of the ventral 

 surface. I have not been able to satisfy myself as to the 

 mentum, which seems to be monomerous. The four principal 

 spiracles are large and conspicuous, the rest small. There 

 are a great number of circular spinneret-orifices on the dorsal 

 epidermis, and others, smaller and fewer, on the ventral. The 

 anal ring is small and hairless, and the anal tubercles obsolete. 

 At and after gestation the skin becomes much wrinkled, and 

 the insect is then nothing but a bag containing a large number 

 of eggs and larvae. 



Larva, reddish-brown, active, elliptical ; length about ^in. 

 In the early part of this stage the form is proportionately 

 narrow and elongated ; the antennae are moderately long and 

 slender, with five distinct subequal joints, the third joint 

 rather the shortest. The feet are slender, with the tibia 

 shorter than the tarsus ; claw slender ; digitules all fine 

 hairs ; the mentum seems monomerous ; the abdomen tapers 



