Dae ty lop ii ncB. ' 377 



minal and penultimate tracts conspicuously larger and stouter than those on the 

 remaining tracts ; caudal setae scarcely longer than those of the anal ring ; 

 tarsus approximately one-third length of tibia. 



Risso's original description of Dorthcsia citri, in his Histoire Nattirelle des 

 Orangers (pp. 252-3), gives very meagre details of the character of the insect. 

 We have, therefore, to rely principally upon circumstantial evidence in fixing 

 the particular species to which that author was referring. The nature of this 

 evidence may be gathered from the following translation of the paragraphs 

 relating to D. citri. 



'The greatest scourge of the Orange tree, and especially of the Lemon, is a 

 kind of scale-insect, which one of us has placed— for the time being — in the 

 genus established by M. Bosc under the name of " dorthesies " {Dorihesia 



citri) This hemipteron has the body oblong oval, convex above, slightly 



swollen below, of an ashy-grey colour, passing to pale yellowish, covered with a 

 cottony white powder, with some appendages on the sides ; the posterior limbs 

 longer than the anterior. The male differs from the female in having two long 

 transparent wings, with two silky filaments which project beyond the body; 

 they are not common ; the female, on the contrary, covers itself with white 

 cottony matter, which she spreads over the leaves, flowers and fruits, and in 

 time she covers with it the ends of the branches. It is in the midst of this 

 down that she lays 150 to 400 yellowish eggs. 



PSEUDOCOCCUS CITRI CULUS,;?07/. 

 (Plate CLIV.) 



Adult female (/^. i) obovate, broadest across the abdominal region ; de- 

 pressed. Dorsum closely covered with white meal which — in some examples- 

 is thickened on the median and lateral areas of the abdomen. Margin with a 

 complete fringe of thirty-four longish white mealy tassels which are shorter 

 in front and increase gradually in length towards the posterior extremity, the 

 terminal pair considerably longer— usually twice the length of any of the others. 

 A pair of ligulate waxy processes from the anal orifice. Antenna {fig. 2, 3) 

 eight-jointed, slender ; the third usually the longest, markedly longer than the 

 eighth {fig. 2), but sometimes rather shorter {fig. i) ; fourth to seventh approxi- 

 mately, equal, shortest ; occasionally there are traces of an imperfect division of 

 the eighth {see fig. 2). Limbs slender { fig. 4) ; tarsus approximately half the length 

 of the tibia ; ungual digitules slightly dilated ; tarsal digitules slender, minutely 

 knobbed at extremity. Anterior and posterior foveas well-marked. Marginal 

 ceriferous tracts well defined ; ceriferous spines sharply pointed, three spines 

 on each of the first, second, third, and sixth tracts, two on each of the remaining 

 tracts, those on the terminal and penultimate tracts distinctly larger than the 

 others ; each tract with a cluster of circular pores and from two to four slender 

 setae (see figs. 3, 6, 7). Caudal setae comparatively short. Anal ring with six 



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