106 MISCELLANEOUS STUDIES 



Records. Cucumis spp. ; Newcastle, Placer County, Watsonville, Santa Cruz 

 County (Clarke); Imperial County (Weldon) ; San Diego County, June, 1916: 

 Cucurbita spp.; Alpine, San Diego County, June, 1916: Citrus spp.; Santa Paula, 

 Claremont (Essig), Acampo, San Joaquin County (Games), San Diego, March, 

 1916 (E. E. McLean); Whittier, May, 1917: Heracleum lanatum; Berkeley, 

 March, 1915 (Essig): Begonia; Stanford University, February, 1912 (Morrison), 

 Biverside, January, 1917; Punica granatum, Stanford University, April, 1911 

 (Davidson): Helianthus; Santa Ysabel, San Diego County, May, 1916: Pcrsea 

 gratissima; Avondale, San Diego County, August, 1916; Chrysanthemum; 

 Ontario, January, 1917; Esclischoltzia calif omica ; Ontario, January, 1917: 

 Anthemis spp.; Pasadena, April, 1917 (E. E. Campbell): Pyrus spp.; Santa 

 Cruz County (Volck), Nevada County (Norton). 



The melon or cotton aphis is distributed throughout the state and 

 is found on a large number of host plants. On melons it is often a 

 considerable pest, particularly in the Imperial Valley. In the apple 

 sections of Santa Cruz and Nevada counties it often becomes abundant 

 enough upon the young trees to cause considerable damage, according 

 to County Horticultural Commissioners Volck and Norton. In San 

 Diego County the author found an infestation on young avocado trees 

 which was very severe. Oftentimes it becomes quite abundant in 

 nurseries and greenhouses. 



124. Aphis hederae Kalt. 



Kaltenbach, Monog. d. Pflanzenlause, p. 89, 1843 (orig. dese.). 



Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. A. rumicis Linn, (list in 



part). 



Essig, Pom. Jour. Ent., vol. 2, p. 335, 1910 (desc.). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. A. rumicis Linn. (list). 



Records. Hedera helix; Stanford University (Davidson), March, 1912 (Mor- 

 rison) ; Claremont, Los Angeles County (Essig) ; San Jose, May, 1911 (Davidson, 

 Morrison); Oakland, November, 1916 (Davidson); Berkeley, April, 1915; Lemon 

 Grove, San Diego County, March, 1916; Eiverside, October, 1916: Chcnopodium 

 sp., Walnut Creek, Contra Costa County, May, 1915 (Davidson). 



Throughout the San Francisco Bay region and southern Califor- 

 nia a small dark brown to black aphid is often found in colonies on 

 the tender shoots of English ivy. Essig described it as Aphis hederae 

 Kalt., but later it was believed to be Aphis rumicis Linn. (A. euonomi 

 Fabr.). However, a careful study of a large series of specimens of 

 this aphid from ivy and of A. euonomi Fabr. from a number of dif- 

 ferent host plants has convinced the author that they are distinct. 

 Gillette is of the same opinion. Consequently the species from ivy 

 in California is Aphis hederae Kalt. In the author's collection there 

 is a specimen from Chenopodium sp. taken by Davidson that appears 

 to be the same species. The most noticeable difference between this 



