230 CHAS. K. BRAIN. 



132. Chionaspis exalbida, Ckll. (Plate xv, fig. 151). 



Chionaspis exalbida, Ckll., The Entom.. xxxv, p. 112, 1902. 



The following description is made from material which I find in this collection 

 labelled " On aloe, Howick, coll. Fuller, Part of original material submitted to 

 Prof. Cockerell, No. 5 of second lot sent Sept 21, 1901." I am somewhat disturbed 

 because I am satisfied that the label is correct, but the characters do not agree 

 with the description given by Prof. Cockerell. I have an abundance of material 

 on aloe from different parts of the country, but I have failed to find in this a species 

 which is without circumgenital glands and which could thus agree with the description 

 given of exalbida. 



The scales of the adult females agree perfectly with the description given. They 

 are massed together in large numbers so as to cover entirely large patches of the 

 leaves. They are about 1 '6 to 2 mm. long, narrow, in some cases shghtly broadened 

 and flattened behind. The secreted portion is dull white and smooth, not markedly 

 chalky, but varying considerably in texture and in the prominence of the transverse 

 growth lines. The exuviae are yellowish or orange-brown, the second pellicle 

 being covered by a layer of secretion, except at the posterior end, which remains 

 naked. In old dry specimens the anterior portion of the second pellicle often 

 shows through the secretionary layer greyish in colour. 



The male puparium is similar but smaller, with parallel sides, and usually + 

 distinctly tricarinated, with the median ridge well pronounced. In a few examples 

 the margins are low, giving the impression that the puparium is uni-carinate. 



The adult $ turns green in boiling KOH. When cleared and mounted the insect 

 is about 1 mm. long and 0"4 mm. broad, narrowed at each end, and slightly widest 

 behind the middle. The body is entirely transparent, the pygidium not appearing 

 more highly chitinised than the remainder of the body. The antennae are prominent, 

 + oval tubercles ; the margin of the abdominal segments are not produced ; there 

 appears to be one comparatively large gland-pore lateral to each of the anterior 

 spiracles. The characters of the pygidium are very indefinite. There are probably 

 two pairs of lobes, as indicated in the figure, but the projecting parts are very 

 delicate, and these, as is also the case with the plates, are often bent back in mounting, 

 and in many instances they might be considered absent (fig. 151). There are 5 

 well defined groups of circumgenital glands, the median with 8 to 14, the anterior 

 laterals with 13 to 18, and the posterior laterals with 6 to 11, usually 10. 



Remarks. What I consider to be a variety of this species is found on aloes in 

 Johannesburg. The female scales appear slightly larger than normal for the species, 

 and the secreted portion of the scale is somewhat roughened, almost felted. The 

 first exuviae are usually yellowish brown and the secretionary layer over the second 

 pellicle appears to extend further back than in typical exalbida, but in stored material 

 it is usually flaked off. The exuviae of the male puparia are generally a little 

 darker than in the type. 



In mounted material the pygidium presents the same indefinite characters ; but 

 in looking over a number of slides it appears that the plates are possibly a little 

 more delicate and hence more often appear to be absent, and the lobes a little 

 longer and narrower. 



