66 THE CALIFORNIA SPECIES OF MEALY BUGS 



Genus TRIONYMUS Berg 



Pseudococcine forms with normally not more than three or four 

 pairs of cerarii, these on the posterior portion of the abdomen. Derm 

 never pigmented. Dorsal body setae never conical or "spearhead-shaped." 

 Dermal pores of the triangular type present. Dorsum frequently with 

 many multilocular pores. Claw without a denticle. Antennae of the 

 adult female 7- or 8-segmented. 



Type of the genus, Trionymus perrisi (Sign.). 



Notes : The type species of this genus has been well described by Marchal 

 (7) and its nature is sufficiently clear. It is evidently very similar to T. califor- 

 nicus Ehrh. The genus was originally established chiefly upon the elongated form 

 of the female, but this can hardly be considered sufficient. If the genus be main- 

 tained at all it must be on the basis of the reduced number of pairs of cerarii, and 

 such an interpretation will necessitate its extension to include several species now 

 referred to the genus Ripersia. I cannot believe that such species as Trionymus 

 bromi n. sp. and Ripersia festucae Kuwana should be separated generically simply 

 because of the difference of a single segment in the antennae, nor, if this interpre- 

 tation be accepted, can I at present see any way by which such species as Ripersia 

 villosa Ehrh. or Pseudococcus trifolii (Forbes) can be kept out of this genus. 



As a matter of fact such a step, even though it result in creating a somewhat 

 unnatural group, can produce no worse confusion than that at present displayed in 

 the genus Ripersia. The real nature of this genus cannot be determined, for it 

 was originally based simply upon the 6-segmented antennae of the adult female of 

 the type species and this is practically the only significant fact that we possess in 

 regard to this species. As at present understood the genus is made to include 

 almost any species with 7-segmented antennae occurring on grass, roots or with 

 ants. Even though the descriptions of practically every one of the North Ameri- 

 can species are hopelessly inadequate, it is obvious that the group thus obtained is 

 a most heterogeneous assemblage and is for all practical purposes meaningless. 



KEY TO CALIFORNIA SPECIES. 



1. With but one pair of cerarii, these on anal lobes 4 



With at least two pairs of cerarii 2 



2. Anal lobe cerarii surrounded by a chitinized area bearing 



numerous pores and setae . . . calif ornicus Ehrh. 

 Anal lobe cerarii not so 3 



3. Antennae of adult female 8-segmented calceolaria* (Mask.) 

 Antennae of adult female 7-segmented festucae (Kuwana) 



4. Cerarian spines setiform distichlii n. sp. 



Cerarian spines conical 5 



5. Cerarii without grouped pores 6 



Cerarii with numerous pores .... grindeliae n. sp. 



