Aphididae of California. XT' 



BY E. O. ESSIG 

 UNIVERSITY OF CALIFORNIA, BERKELEY, CALIFORNIA 



A New Lachnus Attacking the Japanese Dwarf Silver 



Spruce 



Laclinus glehnus n. sp. 

 (Figs. 1-3) 



This species is of medium size and often occurs in great numbers 

 upon the host. It was so abundant in the Capitol Park, Sacramento, 

 California, during the summer of 1912 that control measures were 

 adopted to suppress it. Though the species was abundant upon 

 two trees in the park, it was not found attacking any of the numer- 

 ous other conifers in the immediate vicinity, showing that it has a 

 decided preference for the one host, the Japanese dwarf silver 

 spruce, Picea glehni Mast., which is said to have been imported 

 from Japan a number of years ago. There is no tangible way of 

 accounting for its presence upon this particular tree other than it 

 may have been imported from Japan along with the young plants 

 and have persisted upon them ever since. It has some characters 

 common with Lachnus pouderosa Williams, as will be seen in exam- 

 ining the differences pointed out by John June Davis near the end 

 of the article. 



The following description is based upon two selected individuals, 

 a winged and an apterous viviparous female, which have been des- 

 ignated as types. In addition to these the writer has examined 28 

 mounted winged viviparous females and 37 mounted apterous vivi- 

 parous females. Unless otherwise stated the descriptions will refer 

 only to the type specimens. 



* This is a continuation of the series of articles entitled "Aphididae of Southern 

 California" by the same author. 



