290 AGRICULTURE OF MAINE. 



abundance of a new spruce leaf miner and the occurrence of 

 other spruce insects have turned much of the attention toward 

 the conifers, both native and those introduced for ornamental 

 purposes. The increase of the Gypsy moth area and the con- 

 tinued spread of the brown-tail moth have given the emphasis 

 of one more year's experience with these tv/o pests of para- 

 mount importance. The season has been so favorable to the 

 development of scale insects that even those species ordinarily 

 little noticed have been conspicuous in many parts of the State. 

 Fortunately correlated with the abundance of injurious species 

 the insects of 1912 have included beneficial species in great num- 

 bers. The syrphus maggots and other predaceous insects, for 

 instance, have practically exterminated many species of plant- 

 lice over large areas, and parasites have been actively engaged in 

 their natural warfare against injurious caterpillars and other 

 insects. 



Dr. O. A. Johannsen has completed this year a study begun 

 ten or fifteen years ago of the Fungus Gnats of North America 

 and this Station has published this work in four parts, the last 

 of which contains those gnats of most economic importance, 

 dealing with a group which attacks apples and corn as well as 

 potatoes and other root crops. 



As a basis for studies of New England Psyllids, or "Jump- 

 ing plant-lice," :i series of systematic studies was undertaken and 

 the results of this preliminary work have been published this 

 summer. The "Jum])ing plant-lice" are sucking insects which 

 injure plants in much the same way as the aphifls. This fam- 

 ily of insects has heretofore received such m.eager attention in 

 this country that it has not been possible to recognize some of 

 the commonest species in the United States from the published 

 accounts and many have been known merely as manuscript 

 species. It is proposed to continue this work until we are 

 much better acquainted with the Maine Psyllidae than at present. 



Aphid Investic.ations. 



It is a fact familiar to students of this family of insects that 

 certain aphids live for a few generations (usually wingless) 

 upon one food plant and then produce a winged generation 

 that migrates to an entirely different sf)ecies of plant for the 



