262 The University Science Bulletin. 



on dorsal edge occupies the apical fifth of the valve; the two valves of the pair 

 differ as to number and arrangement of teeth ; the shorter, narrower valve bears 

 many small, regular teeth along its dorsal edge; the longer, broader valve bears 

 thirteen large primaiy teeth along its dorsal edge, these rounded, regular, and 

 bear one to three secondary teeth along their caudal edges; the tip is notched 

 with small teeth on both dorsal and ventral edges, not continuous around the 

 tip, seven on \entral edge of valve bearing small teeth, eleven on ventral edge 

 of valve bearing large teeth; area of ducts conspicuous, ducts easily visible, 

 elongate, rather few in number; open at apex, along dorsal edge of toothed 

 area, and in basal area; no distinct chitinous connection present. 



Empoasca smaragdula (Fallen). 



(PI. XXXIII, fig. 11.) 



Length, 2 mm.; greatest width, 0.11 mm. Narrow and rodlike, about the 

 same width for entire length, tapers caudad at apex; distinctly curved, tip 

 narrowed, extreme apex narrowly rounded, chitinization medium; strengthen- 

 ing rod extends caudad as far as third dorsal tooth. Toothed area on dorsal 

 «dge occupies about the apical seventh of the length; the two valves of the 

 pair are not identical; the one is shorter, narrower, and bears only very small 

 teeth along its dorsal edge ; the longer, wider valve beai-s thirteen large primary 

 teeth along its dorsal edge, flatly rounded, fairly regular as to size, shape and 

 spacing; bear a few indistinct secondaiy teeth; the tip of the larger valve is 

 notched with small, indistinct, irregular teeth on both dorsal and ventral edges, 

 continuous around the apex; area of ducts conspicuous, ducts easily visible, 

 elongate, few in number; open at apex and along basal shaft; the dorsal edge 

 of the basal shaft is irregularly roughened; no distinct chitinovis connection 

 present. 



Empoasca obtusa Walsh. 



(PI. XXIV, fig. 14: pi. XXXIII, fig. 12 ) 



Length, 0.9 mm.; greatest width, 0.05 mm. Consi.-ts of a narrow, rodlike 

 basal shaft and a slightly wider, toothed apical portion which tapers caudad 

 to apex; distinctly curved, tip only slightly narrowed, extreme apex broadly 

 rounded, chitinization moderately light; strengthening rod extends caudad 

 as far as second dorsal tooth. The two valves of the pair are not identical; 

 the shorter, narrower valve bears only very small, regular teeth along its 

 dorsal edge; the longer, wider valve is toothed along its apical seventh with 

 seven primary teeth, these of medium size, rather flatly rounded, fairly regular 

 as to size, shape and spacing, though smaller apically, and bear a few irregular, 

 indistinct, secondary teeth; no distinct teeth present on tip; area of ducts 

 rather conspicuous, ducts visible, few in number, elongate; open apically, 

 along dorsaledge of toothed area, and along basal shaft. 



Empoasca livingstoni (iillette. 



(PI. XXXIII, fig. 14.) 



Length, 2 mm.; greatest width, 0.11 mm. Narrow and rodlike, about the 

 same width for entire length, tapers caudad at apex; distinctly curved, tip 

 greatly narrowed, extreme apex ends in acute-angled point, chitinization very 

 light; strengthening rod extends caudad as far as fifth dorsal tooth. The two 

 valves of the pair are not identical; the shorter, naiTower valve bears only 



