OF WASHINGTON, VOLUME XVIII, 1916 15 



most salient characters for the purpose. The absence of pores 

 at the bases of the anterior and posterior coxae and the larger 

 pores on some of the dorsal plates in this stage are some of the 

 characters specifically distinguishing it from others. 



In Jour. Econ. Ent., in, 342-343, August, 1910, Dr. Felt reports 

 the discovery of a Chermes on Nordmann's firs imported from 

 Europe which was provisionally determined by himself and Dr. 

 "Hopkins as Chermes piceae Ratz. The writer examined also 

 this material, which consists of egg masses and old females on 

 the bark of a terminal shoot, and the evidence tends to show that 

 it is probably the young fir shoot bark louse (Chermes (Dreyfusia) 

 nusslini C.B.) which, biologically by Nusslin and later morpho- 

 logically by Bonier, has been found distinct from that living on 

 the trunk, the latter never going to the young growth. 



The evidence, therefore, is at hand that the fir trunk bark louse 

 has been in this country for at least seven years; and, judging by 

 the location and the heaviness of the infestation of the bark 

 collected by Dr. Hopkins, the insect must have been in this 

 country a good many years, the exact or even approximate num- 

 ber of which we will perhaps never be able to trace. As regards 

 Chermes nusslini, Dr. Felt's note above referred to does not 

 indicate whether any action has been taken to exterminate the 

 colony on imported Nordmann's fir, so that we are not able to 

 say whether or not that introduction led to its establishment in 

 this country, if indeed, like Chermes piceae, it has not already 

 been long established here. 



In Europe both these species are practically confined to fir trees, 

 and while they are presumed to have an alternate host, this host 

 i> not known. Nor are even all the generations known. 



In his " Conif eren-Laiise Chermes," published in 1907, Cho- 

 lodkovsky records a Chermes that was sent him by Prof. Bouvier 

 who collected it in one of the Paris parks on an American fir 

 (Abies nobilis var. glauca) which Cholodkovsky designated as 

 Chermes piceae, var. bouvieri. The morphological reasons for 

 separating the variety are slight, but the fact that it produced 

 y,;ill-like thickenings on the bark and buds was a rather marked 

 biological difference. Nevertheless, in his article in the "Zool. 

 Anzeiger," xxxni, after describing nusslini and discussing its 

 relations. Bonier remarks on p. 750: "As Cholodkovsky's var. 

 bouvieri is identical with the true piceae (and not a hunger form 

 of nusslini, as I was wont to believe), we do not know whether the 

 European piceae attacked the American silver fir after its intro- 

 duction into Europe, or whether this species occurs also in North 

 America and there, completes its normal cycle, and must pa- 

 tiently await further discoveries on the geographical dislril>uii<m 

 of Chermes piceae. 



