Maskell. — On Coccidas. 63 



Planchonia ventruosa, sp. nov. Plate VI., figs. 5-11. 



Test of adult female green, waxy, flat or sometimes 

 slightly concave. The green colour is in the test itself, and 

 not due to the insect showing through it. Form of test 

 broadly elliptical, or with a very slight posterior tapering. 

 Fringe pink or white. 



Test of male glassy, greenish- white, elongated-elliptical, 

 convex. 



Adult female dull dark-red ; form subcircular, or slightly 

 tapering posteriorly; length, about ^in., but rather variable. 

 The dorsum is flat or slightly concave, the ventral surface 

 somewhat prominently convex and wrinkled, the rostrum 

 being situated at the apex, subcentral. Antennae and feet 

 absent, but the position of the antennas is indicated frequently 

 by two very small tubercles. x\nal tubercles very minute, and 

 only noticeable from the two short setae. The margin of the 

 body bears the usual rows of figure-of-eight spinnerets, from 

 which springs a fringe, which is sometimes pink, sometimes 

 white, apparently according as the bark of the tree is dark or 

 light-coloured. The mentum is short and monomerous ; setae 

 short. 



Female of the second stage red ; elliptical. The thin green 

 test is more convex than in the adalt. 



Larva red, covered with thin fragmentary green wax ; 

 elliptical, tapering posteriorly; flattish ; length, about ^in. 

 Anal tubercles prominent ; setae moderate. Antennae short 

 and thick, with six subequal joints. Feet moderately long 

 and slender; digitules fine hairs. On the margin of the body 

 is a row of strong spines, which bear a fringe of feather-shaped 

 segments. 



Male imknown. 



Hab. In Australia, on Acacia sp. I have specimens from 

 Adelaide, sent by Mr. Koebele, on twigs with dark-red bark, 

 and in these the fringes of the adult are pink; others, from 

 Sydney, sent by Mr. Froggatt, are on twigs with lighter and 

 greyish bark, and the fringes are white ; but otherwise the 

 specimens are identical. This insect forms for itself depres- 

 sions or pits in the bark, adapted to the convexity of its 

 ventral surface ; and, when it is lifted out, there remain 

 slender, white, cottony trails, denoting the spiracular regions. 



The flat or concave dorsum and the protruding ventral 

 region distinguish this species. The test is very apt to fall off, 

 contrary to the usual rule in this genus, where it is generally 

 not easy to extract the insect ; and a large proportion of the 

 adults are naked. The variation in colour of the fringe, 

 apparently according to the food-plant, is a point strongly in 

 favour of my theory as to the relationships of Planclionia. 



