95 



NOTES ON SOME BRITISH AND EXOTIC COCCIDjE (No. 20). 



BY J. W. DOUGLAS, F.E.S. 



Plate I. 



Lecanium nigettm. 

 Lecanium nigrum, Nietner, Enemies of Coffee Tree, p. 9 (18G1) ; E. T. Atkinson, 

 Journ. Asiatic Soc. of Bengal, vol. Iv, p. 284 (1880) ; E. Ernest Green, Indian 

 Museum Notes, vol. i, p. 117, pi. vii, figs, a—k (1889). 

 $ adult. Scale long-oval, a little narrowed and produced in front, brown-black, 

 or black, smootli, shining, arcuate lengthwise, gibbous in the middle, slightly and 

 very briefly carinate on the marginal area in front, on each 

 side of the median portion a row of small fovese (some- 

 times wanting), margin not produced, the sides next to 

 it punctured. Under the microscope the whole surface 

 is seen to be covered with tesselation of closely approxi- 

 mate, small, yellow dots and punctures. The scales full 

 of pink eggs and larvse of ordinary form. Antennae of 3 

 joints (fig. 1 in margin) ; the first two broad, short, 

 equal in length ; 3rd longest of all ; 4th and 5th equal, 

 each half the length of 3rd ; 6th and 7th equal, shorter 

 than 4th and 5th ; 8th gradate, pointed, as long as 6th 

 and 7th together (in some specimens it is constricted and 

 simulates two joints), with five or six long hairs, one of 

 them (apical) much the longest ; the other joints, except 

 3rd and 4th, with one or two hairs each. Legs (fig. 2 in 

 Fig. 1. l"'ig. 2. margin) long, slender ; coxae with one very short hair; 



trochanters with one very long hair ; femora with two very short hairs near the 

 apex ; tibiae and tarsi in length subequal, their articulation distinct ; digitulcs of 

 tibiae fine, ordinary ; those of the claw long, broad, much dilated at base and apex 

 as figured, less so in exceptional examples. Length, 3"5 — 4 mm. 



On stems and midribs of the under-side of leaves of Justicia 

 MacdonaJcli, received bj Mr. S. J. Mclntire from the Botanic Gardens, 

 George Town, Demerara, kindly forwarded to me on May 28th, 1889, 

 and, subsequently, a greater number of empty scales on small stems 

 of Comhretum Avhhtii. These agree fairly well with INIr. Atkinson's 

 scanty description (/. c.) and Mr. (jreen's figures {I.e.) of the ? scales 

 of L. nigrum ; and they are identical with ? scales of that species 

 sent to me in 1888 fi*om Ceylon by Mr. Green, who states that they 

 are numerous on and injurious to coffee trees, Cinchona and Oroton. 

 In the plate quoted he also figures the larva, the male and its scale, 

 but no mention is made by either author of the antennae and legs of 

 the female, of which particulars are now supplied. The scales from 

 Demerara, in nearly every instance, had been attacked by paras-ites, 

 which had caused the antenna? and legs to be at least partially mal- 



