18 NEW CALIFORNIAN APHIDIDAE 



Chrysanthemum cultivated. Berkeley, Essig, 1914; Menlo Park, San Mateo 

 County, March, 1915, apterae; Berkeley, October, 1915, alate and apterae; 

 San Diego, January, 1916, alate; La Jolla, San Diego County, February, 

 1916, apterae; Ontario, San Bernardino Countjs January, 1917, apterae. 



Gnapholiwm sp. (everlasting). Walnut Creek, Contra Costa County, David- 

 son, 1914. 



Grindelia cuneifolia (marsh grindelia). Walnut Creek, Contra Costa County, 

 Davidson, 1915. 



Helianthus sp. (sunflower). San Francisco liay region, Davidson, 1914. 



Senecio sp. (German ivy). Stanford University, Davidson, 1909; ibid, 1914;. 

 Palo Alto, Santa Clara County, February 1915, apterae. 



Senecio mikanioides (ivy senecio). Stanford University, Davidson, 1909 (?); 

 Berkeley, Essig, 1915. 



Senecio vulgaris (common groundsel). Stanford University, Davidson, 1910; 

 Santa Paula, Essig, 1911. 



Following is a description of this species under the name of 

 Aphis senecio new species. Cotype specimens are in the writer's 

 collection and in the collections of E. O. Essig and the University 

 of California. 



Alate viviparous female. — The prevailing color is pale gi-een with the head, 

 thoracic lobes, and markings on the dorsum of the abdomen olive gi-een to 

 black. The head (fig. 6) is olive green to black, almost triangular with a dis- 

 tinct tubercle at the apex of the frons. Antennal tubercles are absent. Eyes 

 are red. The antennal formula is as follows: III, VI spur, IV, V, VI base, 

 I, and II. Segments V and VI have the usual primary and accessory sensoria. 

 On III there are faiily large, circular secondary sensoria, arranged irregularly 

 along the whole length of the segment, and in such numbers as to cause the 

 segment to appear tuberculate (fig. 12). Four specimens from Chrysanthe- 

 mum (Berkeley, October 1915) had the following number of sensoria: 20, 23,. 

 24, 24, 25, 25, 26, 27, Three specimens from Senecio (Essig, Berkeley, 1915) 

 had 20, 22, 22, 22, 22, 23. Five specimens from Amsinckia (Morrison, Stan- 

 ford University, 1912) had 19, 21, 21, 21, 22, 22, 22, 23, 23, 24. Two speci- 

 mens from Baccharis (Stanford University, Ferris, 1916) had 21, 21, 23, 24. 

 The modal number of sensoria appears to be 22 or 23. The secondary sensoria 

 on IV are of various sizes, ranging from very small to almost as large as those 

 on III. They are arranged in a more or less even row, and quite irregu- 

 larly. Of twenty-five segments examined (the same specimens as above for 

 III) two had one sensorium, two had two sensoria, nine had three, five had 

 four, two had five, fom- had six, and one had seven sensoria. The modal num- 

 ber appears to be three or four. The thorax is duU green with the lobes very 

 dark olive brown or black. Small lateral tubercles are present on the pro- 

 thorax. The beak is pale at the base and dark green at the apex, and reaches 

 distinctly beyond the second coxae, in fact almost to the third coxae. In 

 some cases it even reaches to the middle of the third coxae. In this character 



