Chionaspis. 1 05 



CHIONASPIS, Signoret. 



(Plate XXXI.) 



C/iio/iaspis, Sign. ' Essat',' 1869, p. 442 (124). 



Species with female puparium elongate or elliptical : usually dilated behind. 

 Pellicles overlapping ; situate at anterior extremity. Ventral scale variously 

 developed ; either thin and delicate, adhering to the plant ; or stout and 

 remaining attached to the dorsal parts, on the displacement of the puparium. 

 There is a very wide range in the form of the puparium. In some species it is 

 very long and narrow {elongata). In others it is so widely dilated as to appear 

 almost circular {varicosa^ dilatata, biclavis). But in all cases the anterior 

 pellicle will be found to project beyond the margin. 



Male puparium as in Diaspis and Fiorinia; oblong, narrow ; more or less 

 distinctly tricarinate. The secrelionary area is usually opaque white; but in one 

 species {ininutd) it is glassy and transparent. In another species {acuminata) 

 there is a distinct reddish colouring matter in the furrows between the carinas. 

 Very little variety is found in the form of the male puparium in this genus, the 

 chief differences lying in the degree of development of the carinie. 



Adult female oblong. Abdominal segments usually well defined, often 

 produced laterally into conspicuous tubercles {aspidistra^ musscendce). First 

 pair of spiracles situated on the prothorax, close to the rostral apparatus. 

 Second pair, on the metathorax, near its junction with the mesothorax. There 

 are normally three free abdominal segments above the pygidium ; but in two 

 species {galliformcns and simplex) the fourth segment, which ordinarily forms 

 the base of the pygidium, is distinctly separated from the terminal segment. 

 The pygidium is usually provided with a median and two lateral pairs of lobes ; 

 but there are considerable differences in the amount of their development. 

 One or both of the lateral pairs may be obsolete, and in some abnormal forms 

 {e.g.^ simplex) all the lobes have disappeared. Two distinct types are notice- 

 able, which are of assistance in grouping the numerous species : — 



1. Species in which the median lobes are in close apposition, appearing 

 almost continuous {Jig. i, Plate XXXI.). 



2. Species in which the median lobes are separate and more or less 

 divergent. 



The second group may be subdivided into species in which the median lobes 

 project freely from the margin {Jig. 2), and others in which these lobes occupy 

 the sides of a deep median cleft {Jig. 3). These two latter forms, however, 

 merge into each other. One or both pairs of lateral lobes are frequently 

 suppressed, especially in the first group, o which aspidistras may be taken as 

 the type. When present, the lateral lobes are duplex, the mesal lobule usually 

 larger than the other. The squames are tapering and spiniform, the extremity 

 perforate and communicating with small filiform spinneret ducts. On the 

 dorsal surface there are usually definite series of conspicuous oval pores (^Jig. 4), 



