TECHNICAL DESCRIPTION 57 



LeCANIUM HEMISPHiEEICUM (TaEG). 



Lec. hemisphsericum, Targioni-Tozzetti, Studi sulle Cocoiniglie 



1867, p. 27. 

 Lec. filicum, Boisduval. 

 Bog. coffeae, Walker. 

 ? Lec. anthurii, Boisduval. 

 ? Lec. hibernaculorum, Boisduval. 



Adult female, varying in colour from pale brownish-fulvous to deep 

 chestnut brown ; all intermediate shades being represented often on a 

 single plant. The paler iorms are often marbled with brown. There is 

 usually a darker sub-marginal zone, but this is not always apparent. 

 The common form on tea and coffee is bright castaneous, with deep 

 castaneous sub-marginal zone. Even with a hand lens the derm is seen 

 to be closely specked with minute translucent cells. A few small raised 

 waxy patches, arranged in more or less regular rows, on the median 

 dorsal area. Form oval, hemispherical ; the margin usually outturned 

 and slightly flattened, but often concealed by the bulging sides. In the 

 early adult there is a distinct median longitudinal crest and two trans- 

 verse ridges ; but these generally disappear during gestation, though 

 traces of them sometimes remain, especially in starved examples. The 

 dorsal sm-face is highly chitinous and polished. During gestation the 

 ventral area shrinks upwards, until the scale forms simply a chitinous 

 shell filled with innumerable pale pink eggs. At this time the inner 

 marginal surface is dusted with white mealy powder, and where a scale 

 has been detached from the plant, an oval white ring mai'ks its former 

 position. Antenna with eight joints, of which the third is always the 

 tongest and eighth next longest, sixth and seventh always shortest, and 

 equal ; first, second, fourth, and fifth sub-equal, sometimes one, some- 

 limes another, slightly the longer : the fourth dilated at distal extremity 

 and without any hairs. Leg with tarsus about two-thirds length of 

 tibia. Signoret states that this section of Lecanium is distinguished 

 from all others by a "true articulation in the tarsus." If by this he infers 

 that there are two distinct tarsal joints, I have failed to observe them. 

 There is a slight constriction at the middle of the tarsus ; but this is 

 noticeable in many species. Scales of anal operculum irregularly trian- 

 gular ; both inner and outersides somewhat sinuous : outer side consid- 

 erablylongerthanbase. Anal ring with eight stout hairs. Stigmatic spines 

 three median spine long and curved, more than three times length of 

 other two. Marginal hairs numerous, long, distinctly dilated and 

 fringed at apex. Sub-marginal tubercles, five to six on each side •. 

 obscured in old examples. Dorsal area closely studded with numerous 

 well-defined oval translucent cells each with a smaller concentric ring 

 in a deep layer of the derm, and a minute central pore on the surface. 

 The cells towards the margin sometimes appear larger, owing to a paler 

 outer zone rendered conspicuous by the darker ground colour of the 

 margin. The cells of the median area are actually rather larger than 

 those of the margin. Derm of ventral area with numerous minute 

 circular pores communicating with cylindrical ducts. Size very vari- 

 able, even on the same plant. Length 2 to 3 mm. Breadth 1"25 to 2 mm. 



The early stages of the female show a gradual progression from the 

 elongate oval to the broadly oval ; the ridges becoming more marked 



