Chionaspis. 107 



There are no oval pores on the ventral margin. The genital opening is situate 

 at the junction of the mesal and first lateral spaces. There is usually, on each 

 space, a series of three or more minute tubercles, each surmounted by a small 

 spine. In some species oval or circular pores occur, in connexion with small 

 spinneret ducts ; but, when present, they are nearly always smaller and less 

 conspicuous than those on the dorsal surface. The secretion thrown out from 

 the oval pores is in the form of a strap-shaped filament, while the squames 

 produce fine silky threads (see Plate XLIII.,yf^-. 7). 



The above constitutes the normal arrangement in species of which the 

 European Ch. vaccinii may be taken as the type. But numerous exceptions 

 and variations occur, which will be noted in the descriptions of the several 

 species. An arrangement of nearly the same kind was suggested by Mr. 

 A. C. F. Morgan in his ' Observations on Coccid?e, No. 3 ' {Entoinologisis 

 Monthly Magazhie, Feb. 1889, pp. 189 ei seq.). But Mr. Morgan traces the 

 segmental divisions in a slightly different way to those here indicated, and 

 allows for five segments only, no mesal tract being recognised. Mr. Morgan 

 makes the marginal lobe the lateral termination of each segment. I am inclined 

 to place the division laterad of the spiniform squame. 



Adult male as in Diaspis. Antennte usually with a single knobbed hair at 

 extremity. The rudimentary eye seldom prominent, often represented only by 

 an inconspicuous dark spot on genee, or altogether suppressed. 



In all respects the genus Chionaspis approaches very closely to Diaspis. 

 The single point of difference appears to be that in Diaspis the pellicles of the 

 female puparium are completely surrounded by the secretionary area, while in 

 Chionaspis the first pellicle always projects beyond the anterior margin. 



It is remarkable that, out of the twenty-six species here described, twenty- 

 three are at present peculiar to Ceylon, three only {aspidistrcE ., thece., and 

 biclavis) having been recorded from other countries. And it is these very three 

 (presumably imported) species that are alone of any economic importance. 



It is extremely difficult to formulate a really serviceable synopsis of the 

 numerous species at present included in this genus. Many of the species have 

 distinctive characters that can only be appreciated by a comparison of the 

 figures. The following arrangement will serve to indicate the main groups. 



Synopsis of Species. 



I. Median lobes approximate ; their inner edges in close opposition. 



A. Median lobes small and inconspicuous. Anal below genital aperture. 

 ia) Female scale fulvous or reddish brown (occasionally whitish) thin and 



semi-transparent. Male puparia irregularly scattered. 



I. aspidish'o;, 

 ip) Female scale reddish brown ; opaque ; very long and narrow. 



Male puparia arranged in regular order 1. thecc. 



(c) Scale white or greyish ; opaque 3. albizzice. 



B. Median lobes large and prominent. Anal above genital aperture. 



(a) Female scale coated with fragments of the cuticle of the bark upon 

 which it rests 4. iniisscendo'. 



{b) Female scale very thin and semi-transparent : colourless or very pale 

 yellow ; concealed beneath the felted hairs of the leaf. 



5. rhododendri. 



