1890.] 155 



longest of all, in length equal ; 4th to 7th shorter, subequal ; 8th a trifle shorter ; 



9th nearly as long as the 3rd, towards the apes laterally gradate ; the upper joints 



especially with projecting hairs. Legs stout (fig. 2) ; the tibiae two and a half times 



longer than the tarsi ; claws short, with two short knobbed digitules. 



Length, 3 mm. 

 (J unknown. 



On May 2nd, 18S9, Dr. T. A. Chapman, Hereford, sent a small 

 terminal twig o£ oak {Quercus rohur), and among the buds were two 

 young Pseudococci, about 1^ mm. long, livid, with a thin, white, 

 powdery covering ; of these forms the most noticeable character was 

 a series of minute white tufts along the margins of the body ; nothing 

 specific could be determined, and I desired to see adults. On June 1st 

 Dr. Chapman sent a quantity of young oak leaves, to the under-side 

 of which were firmly attached white ovisacs containing at one end of 

 each an adult of the young form described above, all alive and busy in 

 the act of oviposition ; on being turned out of the ovisacs they moved 

 about readily. 



The species resembles Ps. aceris in the great length of the tibise ; 

 but differs in the relative proportions of the several joints of the an- 

 tennae, and, as at once seen, in the structure of the ovisac, which in 

 this species is smooth, and of compact, close texture, while in Ps. 

 aceris it is looser, cottony and brittle ; and although the insect is little 

 more than half the size of Ps. aceris, the ovisac is 8 mm. long, thus 

 much longer in proportion than in that species. Further, Ps. aceris^ 

 also Ps. cesculi, mespili, plnfani, and tdmi, appear to be found only on 

 the trunks of the trees they respectively frequent, whereas Ps. quercus 

 is seen only on the under-side of the young leaves of oak, or casually 

 about their foot stalks. Finally, in view of all the discrepancies 

 between this form and the species hitherto described, I must conclude 

 that it is distinct. 



The figures 1 and 2 are from the drawings of Mr. E. T. Lewis ; 

 fig. 3 by Mr. Morgan. 



CETPTOCOCCUS, n. g. 



The species Coccus fagi, Baerensp., hypothetically referred by 

 Signoret to Pseudococcus {cf., Ent. Mo. Mag ,xxiii, p. 153), has nothing 

 to do wath that genus, and as it does not accord with any other, I 

 suggest for it a new genus, Cetptococctjs ; the characters are in- 

 cluded in those of the species, I. c. It may have some, but not close, 

 affinity with Xylococcus, F. Low (Yerh. k. k. z.-b. Gesells. Wien, 1882, 

 p. 274) ; at present the position of both is doubtful. 



Lewisham : January, 1890. 



