456 ME. HUGH SCOTT ON AN 



Cercococcus eremobius, sp. nov. 

 Fern, adult. Corj^us subrotundura ; supra fortiter convexura, ad latera obsolete trans- 

 versim svilcatura, tribus seriebus longitudinalibus tuberculormn peri)arura eleva- 

 torum, foveis nuinei'osissimis fila albida emitteutibus, insectum omnino tegentia; 

 infra convoxum. Cauda brevis, depressa. 



Adult female. It will thus be seen that the most striking characters are the prolonga- 

 tion of the body to form a perfectly distinct tail terminated by large anal lobes, and the 

 presence of very numerous pits scattered over the dorsal surface, from which emerge 

 long curling threads, which together form the dense white covering that entirely 

 conceals the insect and its ovisac. The ovisac, too, is itself a highly remarkable 

 structure. 



The body of the insect, considered apart from the tail, has a vei'y rounded and convex 

 appearance. Dorsally there is a steep posterior slope down to the tail, which is depressed 

 and considerably below the general surface. Ventrally, the surface of the tail is 

 continuous with tliat of the trunk. No traces of asymmetry, such as are exhibited by 

 the adult females of some species of Lecanimn, are visible. The colour of the specimens 

 preserved in formalin and afterwards transferred to spirit is orange, lighter on the 

 ventral surface. When freshly found they also appeared to be orange, though no close 

 examination was then made. They vary considerably in size ; a large specimen 

 measures about 3^ mm. long by 2f mm. broad, while a smaller one was only about 

 2^ mm. long. Tiiis is no doubt due to differences in the degree of maturity. 



The transverse depressions at the sides of the body are somewhat vague. Posteriorly, 

 where the surface of the trunk slopes down to the tail, there are others extending right 

 across the body. The basal portion of the tail also shows a kind of segmentation, which 

 in the distal part becomes, dorsally, very obscure. The tubercles (PI. 34. fig. 4, a, a) of 

 the median and lateral longitudinal rows are only very slightly elevated. They are 

 serially arranged with respect to the transverse furrows, one tubercle standing between 

 each two depressions. They will be mentioned again in connection with the excretory 

 products of the insect. A description of the pits (PI. 34. fig. 4) scattered so densely over 

 the dorsal surface of the trunk is left till the peculiarities of the integument as a whole 

 are dealt with. 



The ventral surface (PI. 34. fig. 2), with the exception of a few minute setae only 

 visible under a high power of the microscope, is smooth, lacking the pits so numerous 

 on the dorsal. At either side it has two well-marked longitudinal furrows (PI. 34. 

 fig. 2 a, b), into the inner of which open the spiracles. An inconspicuous transverse 

 furrow leads from the inner to the outer longitudinal furrow, at the point where the 

 posterior spiracle is placed. Just in front of the anterior spiracle, the inner furrow 

 converges with and joins the outer. In front of this point of union tbe outer furrow 

 curves round towards the middle line, so that it approaches, but does not meet, its 

 fellow of the opposite side of the body. 



In this anterior part of the furrow lies the antenna (PL 34. figs. 2 c, 3), which consists 

 of a single short chitinous piece, round in surface view, bearing a short thick spine and 

 four or more sette. 



