[7] Edgerton, F. Y.:—“On the Representation of Statistics by Means of Analytical Geometry,” Jour. Roy. Stat. Soc., 1914, Feb., Mar., May, June and July. [8] Elderton, 1. c. [9] Compare Edgeworth, “A Method of Representing Statistics by Analytical Geometry,” Proceedings Fifth International Congress of Mathematicians, Cambridge, 1912. [10] Only a part of the original table appears in the accompanying table. The original values were computed to four places of decimals, but three place numbers are sufficient to illustrate the method of approximating to the solution. [11] Compare “Tables for Statisticians and Biometricians,” Cambridge University Press, 1914. [12] For the statistical details see Elderton, 1. c. [13] As may be seen on examining the Table. A PRELIMINARY LIST OF THE JASSOIDEA OF MISSOURI WITH NOTES ON SPECIES. By EDMUND H. GIBSON and ERIC S. COGAN, U. S. Bureau of Entomology. The following preliminary list of the Jassoidae of Missouri is mainly the result of collections and notes made by the authors during the summer months of 1915. On account of the lack of records for this state the authors were prompted to undertake such a survey. As far as possible collections were made so as to embrace all conditions in different sections, giving some attention to ecological relations. The list comprises some 98 species. BYTHOSCOPIDAE. =Macropsis apicalis= Osb. & Ball. A few specimens swept from weeds at Charleston, Mo., during the late summer. =Bythoscopus distinctus= VanDuzee. Found in great numbers on willows in northern Missouri. =Pediopsis viridis= Fitch. Not common. Taken from willows near drainage canals in southeast Missouri. Somewhat more numerous in northern part of the state. =Idiocerus nervatus= VanDuzee. The only species taken from willows about Chillicothe. =Idiocerus verticis= Say. Listed by VanDuzee as occurring in the state. =Idiocerus crataegi= VanDuzee. Swept from grasses at Chillicothe. =Idiocerus snowi= Gill & Baker. Recorded from Lutesville and Charleston. Feeding on millet and grasses. Nymphs numerous during August. =Agallia sanguinolenta= Prov. Most plentiful in southern part of state. A decided pest of clover and alfalfa. Other food plants include wheat and several weeds. Adults abroad in fields all seasons of the year. Abundant in northern Arkansas. =Agallia constricta= VanDuzee. One of the earliest jassids to appear in the spring. Most numerous on grains. Attacks wheat, rye, oats, alfalfa and grass. Abundant in southern counties. =Agallia uhleri= VanDuzee. Not very numerous. Occurring principally near swamps along the Mississippi River. Also collected from clover fields.