SOME MISCELLANEOUS RESULTS OF THE WORK OF 

 THE DIVISION OF ENTOMOLOGY. 



IV. 



THE TWO MOST ABUNDANT PULVINARIAS ON MAPLE. 



(Pulvinaria innumerabilis Rath v. and Pulvinaria acericola W. & R.) 

 By L. 0. Howard. 



The old and well-known cottony maple scale (Pulvinaria innumera- 

 bilis Rath v.) has been the subject of many published articles on account 

 of its occasional extreme abundance and on account of the conspicu- 

 ous damage which it does to maple shade trees in cities. It is true 

 that the species of the genus Pulvinaria have not as yet been properly 

 and systematically studied in this country, although several investi- 

 gators are now engaged in such work, and it is altogether possible that 

 more than one species is even at this late date confused under Rathvon's 

 name. 



This possibility is emphasized by the comparatively recent discovery 

 by the writer that a form occurring upon maple leaves, and which was 

 figured as long ago as 1868 by Walsh and Riley under the name Leca- 

 nium acericola, a name which was considered by J. Duncan Putnam 

 and subsequent writers as a synonym of Pulvinaria innumerabilis, is in 

 reality a perfectly distinct and thoroughly characteristic species, as will 

 be shown in the second section of this article. So also the closely 

 allied form occurring upon Osage orange to which the name Lecanium 

 maclurw was given by Walsh and Riley in 1868, but which has since 

 been considered to be identical with Rathvon's species, is now consid- 

 ered by Professor Oockerell to be distinct. 



These forms being thus separated from Pulvinaria innumerabilis, 

 there is reason to suppose that careful study may establish the occur- 

 rence of other species living upon maple and allied trees, and that in 

 consequence the true P. innumerabilis may have a more restricted geo- 

 graphic distribution than is here given it. It is worthy of remark, 

 moreover, that Professor Cockerell has described as at least a variety 

 the form occurring upon maple branches in the State of Washington. 

 This he calls P. innumerabilis var. occidentalis. 



7 



