22 A CONTRIBUTION TO THE KNOWLEDGE OF 



Phenacoccus helianthi (Ckll.). 



Type host and locality. From Hellanthus, Las Cruces, N. Mex. 



Material examined. From Pluchea sp. and Solanum sp. at Las Cru- 

 ces, N. Mex. ; Baccharis sp. in the river bottom below Elephant Butte 

 Dam, N. Mex. ; undetermined composite near the University at Tucson, 

 Ariz. ; Ptiloria sp., near Lancaster, Los Angeles County, Cal. 



Habit. Thinly covered with white, powdery secretion, lateral tas- 

 sels equaling perhaps half the width of the body, caudal tassels nearly 

 as long as the body. At maturity forming a slender, white ovisac 5 to 

 10 mm. long. 



Morphological characteristics. With eighteen pairs of cerarii. Anal 

 lobe pair with ten or more cerarian spines and numerous but scattered 

 pores, all surrounded by a distinct but not sharply delimited chitinized 

 area ; penultimate pair with five to eight spines and numerous pores ; re- 

 maining pairs all with but two spines and a cluster of eight to ten pores 

 except for the first two or three pairs, which have four to six spines. 

 None of the cerarii with auxiliary setae. In all, the cerarian spines are 

 rather stout, sharply pointed and slightly constricted at the base. Ven- 

 tral side of the anal lobes without a chitinized area and with but two or 

 three small setae. Spines of the dorsum of the body few, small, in part 

 slender and in part like the cerarian spines but smaller; not forming a 

 small, median cluster on the last segment. Tubular ducts abundant, small 

 without a raised rim about the mouth. Anal ring of normal size and 

 shape, the setae somewhat longer than the diameter of the ring and about 

 equaling the anal lobe setae. 



Notes: This is very close to P. eriogoni Ferris, so close that the figure 

 given for the latter species will apply equally well for P. helianthi. The two 

 differ in habit in the fact that the marginal tassels of helianthi are long and 

 slender, while in eriogoni they are short and stout. Morphologically the two 

 differ in the fact that eriogoni possesses six to eight spines in all the cerarii and 

 appears constantly to have a small cluster of spines (not noted in the original de- 

 scription) on the dorsum of the last abdominal segment. These differences are 

 quite small, but they are constant throughout my material. 



Genus HETEROCOCCUS Ferris. 

 Heterococcus arenae Ferris. 



1918. Heterococcus arenae Ferris, Cal. Species Mealy Bugs, p. 65, text fig. 16C, 

 pi. 3, fig. 32. 



Type host and locality.. From Poa douglasii on the sand dunes at Pa- 

 cific Grove, Monterey County, Cal. 



Material examined. From an undetermined species of perennial 

 grass at the top of the mountain on the road between Big Pine and Deep 

 Springs, Inyo County, Cal. Altitude about 7,000 feet. 



