1830.1 153 



NOTES ON SOME BRITISH AND EXOTIC COCCIDM (No. 16). 

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



PSEUDOCOCCUS ACEEIS. 



Psendococcus aceris, Sign., Ess. Cochen., p. 363 ; E. A. Smith, N. American Ento- 

 mologist, vol. i, p. 73, pi. vi (1880) ; Comstock, Report for 1880, p. 345. 

 Adult ? . Broad-oval, obtuse and broadly rounded in front, pale olivaceous, 

 eventually becoming greenish-ochreous, body thick, tumid above and beneath, surface 

 T\ smooth, punctate, with many fine white hairs, long on the posterior 

 segments ; anal ring large, with six long hairs ; the last segment 

 deeply emargiiiate, the lobes rounded. Antennse long, slender, of 

 (h nine joints, tlie first broad, stout, second smaller, longest of all, 

 the third nearly as long, the others consecutively smaller and 

 shorter up to the ninth, which is longer and pointed, all with few 

 hairs. Tibiae three times longer than the tarsi ; claws short, stout, 



inwardly finely denticulate, with two knobbed digitules (fig-). 



Length 5, breadth 2'5 — 3 mm. 



The A-ery slender antenn.ie became twisted or broken in preparation 

 for tbo microscope by Mr. R. T. Lewis, and did not afford satisfactory 

 drawings ; the legs came out better. 



The abdomen of some of the specimens was distorted by a large 

 swelling on the dorsal surface ; from three or four of these a white 

 Dipterous larva came out, but none of them survived to maturity. 



Now first noticed as British. Signoret says that it is found on 

 maple, hornbeam, Jinie, and horse-chestnut. 



On May 24th and 29th, 1889, I received from Mr. E. Parfitt, 

 Exeter, some examples of this species, which he had found in the 

 crevices on the boles of lime trees, where they were conspicuous by 

 their ovisacs, but there were none on the elms growing with the limes. 

 The ovisac, formed of white, slight, brittle, cottony material, 8 — 9 mm. 

 long and 3^ mm. broad, is closely occupied in the anterior portion by 

 the insect (over which the covering is very thin), the remainder filled 

 with small white eggs. There was no trace of the male. Probably 

 both sexes exist until they are adult on the leaves of the trees ; that 

 after accouplement the males die immediately and disappear, after the 

 manner of Coccids in general, and then the females as a rule travel 

 (as I have seen they are well able to do) to the trunk where, in a 

 secure place, the ovisac may be developed. 



I may here remark that there is much difference in character 

 among the ovisacs of all the species of Pseudococcus that I have seen, 

 consequent, doubtless, on variation of the secreting organs, affording 

 good subsidiary data for estimating specific specialities. 



In his " Report," I. c, Professor Comstock refers to an article in 



