280 ENTOMOLOGICAL NEWS. [June, '09 



American Snowball Louse, Aphis viburnicola n. sp. 

 C. P. GILLETTE, Fort Collins, Colo. 



(Plate XI). 



For the past nine years, at least, I have noticed the injuries 

 of a plant louse which attacks the common snowball ( Vibur- 

 num opulus} in Colorado. At first I supposed this to be the 

 Aphis viburni described by Scopoli,* Shrank and other Euro- 

 pean writers, but I have been unable to harmonize any of the 

 descriptions made in Europe with the louse as I have observed 

 it. According to Scopoli's brief description in Entomologica 

 Carniolica, 1763, the apterous form of this louse is earthy in 

 color at first, becoming black later and with antennae as long 

 as its body. Buckton in British Aphididae, Vol. ii, page 79, 

 quotes Sulzer as saying that the male of viburni is apterous, 

 which is never the case with the species occurring here. Sul- 

 zer' s description I have not seen. Kaltenbach (Monographe 

 der Pflanzenlause, page 78) describes the apterous form of 

 vibiirni as "blackish brown or entirely black * : the young 

 set with strong rather long spines," and the alate form as 

 having the thorax "black, polished; abdomen dark green," 

 and also states that the louse occurs on the bushes from June 

 to October. From the middle of June to about the loth of 

 September the snowball bushes here have been entirely free 

 from this louse. Koch (Der Pflanzenlause, page 122) also 

 describes and figures viburni as a black louse. Buckton' s de- 

 scriptions and figures of viburni are also quite unlike the louse 

 occurring here upon snowball, and especially is this true of his 

 characterizations of the viviparous and the oviparous females. 

 For these reasons I am considering this American species new. 

 Young stem mother, Plate XI, fig. i. 



Specimens from insectary before the first molt. 

 Color apparently ashy gray, but the body is really a very pale greenish 

 yellow and is heavily covered with fine gray powder. Several rows of 

 black dots extend along the median line of the dorsum ; upon the nieso- 

 and metathorax there is a double row upon either side of the median line, 

 and these are continued over about the first five abdominal segments, 

 where the outer rows cease, and the inner ones continue to about the 

 eighth segment. The cornicles are hardly elevated above the surface 

 and appear from above as two concentric black rings, the outer being the 



* I am under obligations to Mr. J. T. MoneJI for a copy of Scopoli's description. 



