130 MISCELLANEOUS STUDIES 



31. Genus Hyalopterus Koch 



Koch, Die Pflanzenlause, p. 17, 1854. Type Aphis arundinis Fabricius ( A. 

 pruni Fabr.). 



153. Hyalopterus arundinis (Fabr.) 



Figures 181, 185, 186 



Fabricius, Ent. Syst., vol. 4, p. 212, 1749. Aphis (orig. desc.). 



Clarke, Can. Ent., vol. 35, p. 247, 1903 (list). 



Davidson, Jour. Econ. Ent., vol. 2, p. 303, 1909 (list). 



Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). 



Essig, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 569, 1913 (list). 



Essig, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 624, 1913. A. prunifoliae 



Fitch (list). 



Weldon, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 630, 1913 (list). 

 Weldon, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 378, 1914 (list). 

 Patch, Maine Agr. Exp. Sta., Bull. 233, 266, 1914 (dese.). 

 Davidson, Mon. Bull. Cal. Comm. Hort., vol. 6, p. 64, 1917 (note). 



Records. Prunus spp., Phalaria, arundinacea, Phragmites communis, Typha 

 latifolia; central California. 



During the spring and early summer of the year this ' ' mealy-plum 

 louse" is often very abundant on various species of Prunus in the 

 central part of the state, especially in the San Francisco Bay region 

 and the Sacramento Valley. As summer continues all the aphids 

 desert the plum for other host plants, where they remain until fall. 

 The summer hosts in California so far known are reed grass, canary 

 grass, and tule, or cat-tail rush. In the Santa Clara Valley there is a 

 feeling among the prune growers that this aphid is the cause of the 

 splitting of the prunes, which is often quite extensive. However, this 

 remains to be proven. 



32. Genus Liosomaphis Walker 

 Walker, The Zoologist, p. 1119, 1868. Type Aphis berberidis Kalt. 



154. Liosomaphis berberidis (Ealt.) 



Figures 184, 251, 252 



Kaltenbach, Monog. d. Pflanzenlause, p. 85, 1843. Aphis (orig. desc.). 

 Davis, Ann. Ent. Soc. Am., vol. 1, p. 254, 1908. Bhopalosiphum (desc.). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 378, 1910. Bhopalosiphum (list). 



Eecords. Berberis vulgaris; Stanford University (Davidson); February to 

 May, 1915; Berkeley, June to August, 1915. 



This species is found throughout the year on the lower sides of 

 the leaves of barberry in the San Francisco Bay region. The apterae 

 are often very abundant, but the alates are always quite scarce. This 



