300 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Sek. 



282. Thamnotcttix vespertinus Ball. Niles Canyon. May, 

 1916. 



283. Thamnotcttix visalia Ball. San Francisco, July 18, 

 1916; Santa Cruz Co., 1200 feet, June 8, 1917; Muir Woods, 

 July 15, 1917; Niles Canyon, May, 1916; June 13, 1917; 

 July 6, 1916; Redwood Canyon, July 2, 1916; near Stockton, 

 May 30. 1916. 



284. Thamnotcttix vapidus Ball. Near Lakeport, Lake 

 Co., 2500 feet, August 2, 1916; Placer Co., August 22, 1916; 

 Fallen Leaf Lake, August 21, 1917. 



285. Thamnotettix dissimilata Ball. Placer Co., 3900 feet, 

 August 20, 1916. 



286. Thamnotettix helvinus, new species 



Size and aspect of gemellus, but without the fuscous shade on the 

 elytra ; female segment abruptly produced and black at apex. Length 

 4^ mm. 



Vertex longer and more angled than in gemellus; obtusely right- 

 angled at apex ; one-third longer on the middle than next the eye ; disk 

 a little depressed, the anterior edge a little rounded. Front broad, and 

 strongly convex. Clypeus narrowing to the apex with the sides regularly 

 but feebly arcuated. Pronotum a little shorter than the vertex. Elytra 

 long and narow as in gemellus. 



Color light yellow with the disk of the pronotum and elytra green; 

 front smoky fulvous with the arcs pale, sometimes nearly obsolete, this 

 smoky color forming a siniiated line on the anterior submargin of the 

 vertex, thus indicating the reflected base of the front ; eyes, ocelli, incised 

 median line of the vertex and the facial sutures slenderly black. Scutellum 

 sometimes tinged with green. Elytra green on their common disk, becom- 

 ing hyaline toward the costa and apex, with pale yellow nervures, the ex- 

 treme tip slightly infuscated. Tergum, its apex and margins excepted, 

 the oviduct and apical tooth of the last ventral segment of the female 

 and the tarsal claws black; spines of the hind tibiae set on minute black 

 points. 



Last ventral segment of the female strongly and abruptly produced in 

 a convex black tooth over the base of the oviduct ; lateral angles pointed 

 but not attaining the line of the median tooth. Valve of the male short 

 and truncate ; plates long-triangular, subacute, the submarginal groove 

 distinct but scarcely discolored, their margins apparently unarmed ; py- 

 gofers not surpassing the plates, with a corona of stout white bristles at 

 apex. 



Described from two male and ten female examples taken 



as follows: Crystal Springs, San Mateo Co., June 25, 1916; 



Santa Cruz Co., 1500 feet, June 8, 1917; San Mateo Co., 



June 17, 1917; Portola Valley, San Mateo Co., May 4, 1917; 



Seattle, Wash., July 7, 1917, taken by Mr. GifTard, and Cor- 



vallis, Oreg., May 26, and June 29, 1896, by Mr. Thayer. 



This small slender green species may be distinguished by the 



