l6o MAINE AGRICULTUILAIv EXPERIMENT STATION. I912. 



enough and needs no other explanation for the arrangement of 

 the present paper. As a convenient bibhography, which at the 

 same time throws into comparison collections from the same 

 and related plants from other parts of the world, there is ap- 

 pended a host plant catalogue of the aphids of the world cov- 

 ering the corresponding group of plants. 



The plant lice included in this paper are those infesting the 

 Ferns, Conifers, and Monocotyledons. 



Ferns. 



But one species on ferns has as yet been chanced upon in the 

 Maine collection and that is Mastopoda pteridis Oestlund, a 

 peculiar species with atrophied tarsi taken on brake fern 

 (Pteris aqiiilina L.) Aug. 6, 1906, near Orono. An account of 

 this collection is given in Bulletin No. 182 of this Station. 



CoNiEERS. 



Several genera of aphids occur upon Conifers in Maine and 

 all are of economic importance. Of these Mindarus abietinus 

 Koch is very troublesome upon the new tender growth of spruce 

 and balsam fir in the spring of the year, producing a ruffled 

 appearance of the needles on infestfed twigs. Accounts of this 

 species are given in Bulletins 182 and 187. 



Seven species of Chermes are injurious to spruces, pines and 

 larches in Maine. Chermes pinicorticis Fitch has "been dubbed 

 "Prne blight" by virtue of the white secretions of a colony on 

 the bark of infested pine, and is a serious enemy to young white 

 pines both in nursery stock and in the open. Chermes pinifoliae 

 Fitch (abieticolens Thomas) causes a cone shaped gall on black 

 spruce, the migrants from which seek the white pine and deposit 

 eggs upon the leaves so that the nymphs have the tender new 

 growth of white pine to feed upon. They can be detected by 

 the sickened appearance of the pine shoots and the flocculent 

 secretion of the young Chermes when numerous. Chermes 

 abietis Cbolodkovsky inhabits the "pine-apple gall" of white and' 

 Norway spruces and is a common nuisance wherever these trees 

 are used for ornamental purposes, for the affected branches 

 become stunted and deformed. Chermes lariciahis Patch pro- 

 duces a ''pine-apple gall" on white spruce very much like that of 

 abietis though the needles are shorter and the gall has a general 



