A SYNOPSIS OF THE APHIDIDAE 45 



is a small, slender, long-legged aphid, that clings fast to the pine 

 needles and is extremely difficult to see. However, if a branch of 

 pine is struck sharply and with considerable force over a white paper 

 or cloth, a large number of these aphids will jar off. 



19. Genus Tuberolachnus Mordwilko 



Mordwilko, Ann. Mus. Zool. d. 1'Acad. Imp. Sci., vol. 13, p. 374, 1908. 

 Type Aphis viminalis Fonsc. 



44. Tuberolachnus viminalis (Fonsc.) 



Figure 86 

 / 

 Boyer de Fonscolmbe, Ann. Ent. Soc. France, vol. 1O, p. 162, 1841. Aphis 



(orig. desc.). 



Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. Lachnus (list). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Lachnus (list). 

 Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. Lachnus dentatus Le 



Baron (list). 

 Essig, Pom. Jour. Ent., vol. 4, p. 774 (772), 1912 (list). 



Records. Salix spp., Stanford University and Penryn, Placer County (David- 

 son) ; Ventura County (Essig); Stanford University, November, 1914; Berkeley, 

 July, 1915; Eiverside, July, 1916. 



This extremely large aphid, which lives in large colonies on the 

 branches of various species of willows, is found throughout the San 

 Francisco Bay region, Sacramento Valley, and southern California, 

 although it is not at all common. Davidson reports considerable 

 parasitization by a species of Epherdius, and Essig infection from 

 some bacterial or fungus disease. The large size and the presence of 

 a dorsal abdominal tubercle are distinguishing characters. 



20. Genus Lachnus Burmeister 



Burmeister, Handbuch d. Entomologie, p. 91, 1835. Type Lachnus faciatus, 

 n.sp. 



This is the third largest genus of aphids in regard to the number 

 of species in California. All the species are to be found on various 

 conifers, usually feeding through the bark of the branches or trunk. 

 Characters for distinguishing the species are hard to obtain, and 

 those used by the author in the following key are of no value except 

 with specimens of the alate viviparae. This key is not at all adequate, 

 and is offered here merely as an aid. The author understands that 

 Wilson is preparing a monograph of this genus, which will undoubt- 

 edly prove quite valuable. 



