July, 18S0.J 25 



NOTE ON SOME BEITISH COCCIDM (No. 3). 

 BT J. AV. DOUGLAS, F.E.S. 



Having now before me Foerster's little-known article " Ueber 

 Scbildliiuse," to wbicb I alluded from report only at p. 248, vol. xxii, 

 witb respect to tbe presumable identity of certain reputed species of 

 Lecanium, I can revert to it witb greater precision. He says : — 



" The male of all the species of this genus must be most carefully examined, 

 foi* only on the fully developed males can the specific character be founded with 

 certainty. The early writei-s, mostly without knowledge of the male, named the 

 species after the plants on which the female was found, a mode of proceeding that 

 necessarily led to many species being placed together as a single one, as I have fully 

 proved." .... 



" With respect to the determination of the species, it is not difficult to distin- 

 guish the Coccus tilicB of Reaumur and Linne, for the former has long ago given a 

 figure of it in the 4th volume of his ' Memoires ;' but if it be agreed that the 

 Coccus tilicB of both authors is the same, so also it is incontestable that this Coccus 

 is not limited to the lime tree only, but that it goes to other trees, and in each case 

 is named differently in accordance with its habitat. In former time, and also again 

 this year, I have observed it on the following, namely, Populus tremula, Ulmns 

 campestris, Acer pseudoplatanus, and Prunus padus, also on pear and cherry trees. 

 Further, it appears to me probable that Coccus quercus, hetulce, carpini, coryli, and 

 perhaps also oxyacanthtB, Linne, must form one and the same species with that here 

 treated on. Under these circumstances, the name tilice can no longer be retained, 

 and I therefore allow myself to bestow on it a new one, which has reference to the 

 wandering life of the species, and call it Lecanium vagahundum."* 



Tbe soundness of Foerster's tbeory in its entirety is invalidated 

 by tbe fact tbat some of tbe species be mentions, as tbey are now 

 understood, belong to tbe genus Puhrinm la, of wbicb tbe female scales 

 are remarkably different by baving in tbeir ultimate state a protruding 

 ovisac, and tberefore tbey cannot be identical witb any true Lecanium. 

 Sucb a proposition by one baving sucb a rice power of observation as 

 Foerster is incredible, and so it is most likely be bad in view scales of 

 species of true Lecanium, and tbat be misapplied to tbem tbe names 

 he bas quoted ; tbus be may bave bad scales of Lecanium genevense 

 and called tbem oxyacanthee, wbicb is a PuJvinaria, botb species 

 feeding at tbe same time on one kind of tree. Linne did not describe 

 bis Coccus oxijacantli(B (S. N., 742, 21) ; be merely says "Habitat in 

 Cratcpgo oxyacanthee,'^ and refers to " Kcaumur, Ins.," iv, t. 6, f. 11, 12, 

 wbicb figures clearly denote a Pulvinaria witb a protruding woolly 

 ovisac ; whereas, L. genevense bas no external ovisac, and is a true 

 Lecanium. Or it may be that Foerster only saw tbe scales of tbe 



* This is the name quoted by Kaltuubach in his " Pfl.inzenfeinde," of which Signoret had no 

 trace (Ess. Cochin., p. 4(3(5). — J. \V. D. 



