LecaniincB. 229 



LECANIUM NIGRUM, Nietiier. 



(Plate LXXXIV.) 



Lee. nigrum, Nietner, Enemies of the Coffee Tree, p. 9, 1861. 

 I^c. depressum, Targioni-Tozzetti, Stud, sidle Cocciniglie, 1867. 

 Lee. begonia, Douglas, Ent. Mo. I\Iag., Aug. 1892, p. 209. 



Adult 9 {figs. 2, 3) variable in size, form, and colour, such variation depend- 

 ing considerably upon the host-plant. The typical form is irregularly oval, 

 usually asymmetrical, narrowed in front ; strongly convex, the dorsum above 

 the abdominal region sometimes forming a pronounced hump. Neither the 

 stigmatic nor anal clefts are conspicuous. There is often a slight median 

 longitudinal carina and some shallow fovese on the sides. On some plants 

 ifi.g., Mussanda and Ca?ithium), I have found examples almost circular in out- 

 line ; while on the narrow leaves of Asparagus the scales are elongate and 

 narrow, with the margins concealed beneath the protuberant sides. On leaves 

 of Agave, Maranta, and Canna, the scales are usually much less convex and 

 of a much more regular oval form. The colour of the mature insect varies 

 from bright castaneous to deep purple black, the tint usually deepening with 

 age ; but examples on Agave and Canna appear to remain castaneous even 

 when fully mature. Surface smooth, but not highly polished, faintly papillose. 

 During oviposition the ventral parts shrink upwards, leaving a cavity com- 

 pletely filled with eggs. Eyes inconspicuous, submarginal, visible only in 

 macerated specimens. Antenna (fig. 12) with eight joints, of which the third 

 is always much the longest, the eighth next longest, and the ninth the shortest ; 

 the relative lengths of the remaining joints variable. Legs well developed, 

 slender ; tarsus and claw together nearly equal to tibia ; digitules normal. 

 Anal ring with six stout hairs and two finer ones. Scales of anal operculum 

 {fig. 11) with outer edge slightly convex, base slightly concave; outer almost 

 as long as inner edge ; base shortest. Anal cleft almost obsolete, the two 

 edges firmly united. Stigmatic spines acutely pointed, three, the median one 

 about three times as long as the other two ; approximately marginal in the 

 early adult {fig. 5) ; sunk in a small cleft in older examples {fig. 6). Marginal 

 hairs dilated and flattened at extremity, the flattened edge deeply emarginate 

 (fii^- 5i 6). Being set edgeways, the flattening is not always apparent and may 

 be overlooked. Submarginal tubercles, about five on each side, inconspicuous. 

 Derm closely covered with a conspicuous tessellation of irregularly polygonal 

 cells, each with a median pale oval spot and a minute translucent pore in the 

 centre. The appearance of these cells varies considerably in different in- 

 dividuals and even on different parts of the same scale. In less mature scales 

 the cells are separate {fig. 8) ; in more advanced scales the sides of the cells 

 become thickened {fig. 9) ; later, the cells themselves appear to increase in 



