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XII. On Cercococcns eremobius, gen. et sp. nor., an Aberrant Form of Coccidse. 

 £}/ Hugh Scott, B.A. {Cantab.). {Communicated by J. J. Lister, II. A., F.B.S., F.L.S.) y "" ~~"'"n 



(Plate 34.) 



Eead IStt April, 1907. 



1 HE species of Coccid which I have to describe in this paper was found on a desert- 

 plant growing on the hill known as Djebel-el-Melah, " the Mountain of Salt," in one of 

 the southern spurs of the great central plateau of Algeria, where the mountains slope 

 down to the Algerian Sahara, a few miles north of the oasis of Biskra. The hill 

 consists of beds of rock-salt and gypsum overlaid by Cretaceous strata. At this place 

 was growing a specimen of a Cistaceous plant, Helianthemum kahh-icum, Delile, found 

 throughout the Algerian Sahara, and having a general distribution from Syria to 

 Algeria : for this determination I am indebted to Dr. Stapf, of the Herbarium of the 

 Eoyal Gardens, Kevv. The specimen is a dwarf woody shrub, reaching about four 

 inches from the ground. It bears on its twigs conspicuous white masses of a substance 

 somewhat like cotton-wool in appearance. The small oblong-lanceolate leaves of the 

 plant are, as in so many desert-plants, covered with hairs, which are very minute in this 

 case. These hairs give a greyish colour to the plant, but are not otherwise conspicuous, 

 whereas the wool-like masses are decidedly so, contrasting strongly with the leaves 

 and twigs, as will be seen in PI. 34. fig. 1, which shows almost the whole plant. 

 The infected plant was collected on Dec. 25, 1906, by Mr. J. J. Lister, who found that 

 each of the wool-like masses contains a Coccid. Not having^ time to investigate the 

 matter himself, Mr. Lister very kindly handed the material to me for examination. 



I owe my best thanks to Mr. Hobert Newstead for kindly examining specimens, and 

 for pointing out the salient features and systematic position of the insect ; also to 

 Dr. David Sharp for much help and advice in dealing with it. With this assistance it 

 has been possible to make out fairly satisfactorily its characters. 



It is neciissary to form a ncAV genus of the subfamily DactijlopiincB, closely allied to 

 Asterolecanium *, Signoret. The following is a diagnosis : — 



CERCococcrs, gen. nov. 



Fem. adult. Corpus prolongatura, caud^ distincta munitura. Loin anales magni, 

 setigeri. Antenme miuutoe. Insoctum omuino carens pedibus. 

 Maris puparium nullo modo translucens, extrinsecus filis longis. Mas incoguifcus. 



* Aster o-Lecardiim (Targ.), Sign. (1868), Ann. Soc. ent. France, 1869, p. 101 ; Asterolecanium, Targ. 1869 [sec. 

 Fernald, Cat. Cocc. \\ 49], Sign. (180S), Ann. Soc. put. France, 1870, p. 270. . 



SECOND SERIES. — ZOOLOGY, VOL. IX. 05 



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