152 Chionaspis. 



CHIONASPIS BICLAVIS, Comstock. 



(Plate LIV.) 



Chionaspis biclavis^ Comst., Second Report on Scale Insects, 1893, p. 98. 

 Hotvardia biclavis, Berlese and Leonardi, Rivista di Patalogia Vegetate, 

 Anno IV., Num. 7-12, p. 348. 



Aspidiotus tliecE (part), Green, ' Insect Pests of the Tea Plant,' p. 12. 



Female puparium {figs. 3, 4) broadly oval, slightly narrower behind, often 

 almost circular ; convex above. The actual colour of the scale is greyish ; but 

 it is rendered very inconspicuous, and made to harmonise with its surroundings 

 by the incorporation of the superficial fibres and scaly particles of the bark, the 

 natural position and arrangement of these particles being undisturbed {fig. 2). 

 The concealment is so complete that the scales appear only as slight inequalities 

 or minute blisters on the stem of the plant {fig. i). But, where a dead scale has 

 been displaced or fallen off, a conspicuous whitish scar is visible. This habit 

 has earned for it, in America, the name of the ' mining scale.' It does not, 

 however, penetrate beneath the living cuticle of the plant, but, like many of its 

 congeners, insinuates itself beneath the loose outer dead layers of the bark. 

 Frequently the outer covering matter of the scale becomes abraded, revealing 

 the greyish white material of the secretionary area. This form resembles that 

 described by Mr. Maskell as var. detecta. When the scale is formed upon a 

 smooth-stemmed plant, the surface is usually coated with a layer of reddish 

 brown varnish-like material, to match its surroundings. Ventral scale white, 

 moderately stout, remaining adherent to the bark, except around the margin, 

 where it often comes away with the dorsal parts. First pellicle minute and 

 inconspicuous, projecting from the anterior margin of the puparium. Second 

 peUicle completely concealed. Length 2*50 mm. Breadth 2 mm. 



Male puparium unknown. Although the females are extremely abundant, 

 not a single male insect has been observed either in Ceylon or elsewhere. It 

 must therefore be supposed that the young are produced asexually. 



Adult female {figs. 5, 8), broadly ovoid ; broadest across mesothorax ; 

 rounded in front, bluntly pointed behind ; division of segments distinct. Colour 

 varying with age ; at first creamy white {fig. 5); median dorsal area afterwards 

 suffused with pinkish purple ; later, with chestnut brown, by the deposition of 

 chitinous matter, which first appears in definite transverse plates across the 

 meso and metathorax and first two abdominal segments {fig. 6), but afterwards 

 extends over the whole dorsal surface as far as the second abdominal segment 

 {fig. 7). Under surface of older examples dull purplish ; the second and third 

 abdominal segments and base of pygidium whitish. Inconspicuous eye-spots 

 can be distinguished in the early adult {fig. 5). Antenna with four to six stout 

 spines on a thickened disc {fig. 10). Both pairs of spiracles with parastigmatic 

 glands. Second and third abdominal segments each with a marginal group of 



