336 Vniversitij of California Puhlications [Entomology 



quite thick whitish pulverulenee and occurring in dense colonies 

 on the leaves of the young growth of prune and plum trees. It 

 was also taken in considerable numbers on apricot trees at Niles, 

 California, July 11, 1916. The Japanese varieties of plums 

 appear to be immune to their attacks as was exemplified last year 

 at Martinez, California, where a few prune trees growing in a 

 thrifty young orchard of Burbank plums were very seriously 

 attacked, while not a single infestation could be found on any 

 of the plum trees. It is also of interest to know that the cracking, 

 usually a cross, at the ends of prunes in the Santa Clara Valley 



Fig. 21. Hyalopienis arundinis (Fab.) Prunes showing the character- 

 istic splitting at the ends as a result of the j^resence of this insect on 

 the foliage. Morgan Hill, Cal., July 14, 1916. (Original.) 



has been definitely found to be due to the attacks of this insect, 

 according to Horticultural Commissioner Earl Morris, and the 

 annual loss occasioned is sometimes considerable. 



Aphis alhipes Oestlund (fig. 22). The apterous viviparous 

 females are dark with whitish pulverulenee arranged in definite 

 patterns on the back as shown in the illustration. The apterous 

 forms (fundatrix) were taken on the shoots of the snow berry, 

 SympJioricarpos racemosus Michx., on the campus, INlarch 25, 

 1916. Great numbers of both winged and apterous viviparous 

 females were taken from the terminal shoots of the same plant 

 on May 15, 1916. The leaves are often curled in dense irregular 

 masses and form splendid protection for the insects. The species 

 was determined bj^ John J. Davis. 



