36 THE CALIFORNIA SPECIES OF MEALY BUGS 



after the first molt without mouth-parts or cerarii and with a simple, non- 

 setiferous anal ring. 



Type of the genus Pseudococcus longispinus (Targ.) 

 Notes: As the genus is thus defined the species found in California form a 

 quite homogeneous group except for four species in which there has been a reduc- 

 tion in the number of pairs of cerarii. In P. eriogoni the cerarii are lacking on 

 the head and also behind the eyes, there being in all but 9 or 10 pairs instead of 

 the usual 17. In P. salinus certain of the cerarii along the lateral margins just 

 behind the eyes are lacking. Both of these species, however, seem clearly to belong 

 to this group. In P. nipae there is a reduction in the number of cerarii accom- 

 panied by a tendency for the cerarian spines to be so widely separated that in 

 the adult their identity is obscured. In P. aurilanaius there are not more than 

 five or six pairs of recognizable cerarii and in the anteriormost of these the spines 

 are so small and so widely separated that they are scarcely to be recognized. This 

 species, in fact, departs so widely from the typical form of the genus that I am 

 inclined to believe it should be removed. Nevertheless such action would be at 

 present unjustifiable and I retain it in Pseudococcus in spite of the discord that 

 it causes. 



The distinction that I have drawn between Pseudococcus and Trionymus is 

 clear enough as far as the type species of the two genera are concerned, but grad- 

 atory forms may make it difficult to maintain. 



KEY TO CALIFORNIA SPECIES 



1. Anal lobe cerarii with as many as 10 cerarian spines 



crazvii (Coq.) 



Anal lobe cerarii with not more than 2 cerarian spines .... 2 



2. Anal ring very weakly chitinized, almost simple, pre- 



senting a crescentic appearance . . salinus (Ckll.) 

 Anal ring strongly chitinized, distinctly compound, not 



presenting a crescentic appearance 3 



3. With no auxiliary setae in the cerarii anterior to the 



last two abdominal pairs 4 



With auxiliary setae in most or all of the cerarii 12 



4. With no definite cerarii anterior to the last 5-6 abdom- 



inal segments aurilanatus (Mask.) 



With cerarii on the head and thorax 5 



5. Cerarian spines in all except the anal lobe cerarii 



tending to be widely separated, dorsal body setae 



short, stout and conical nipae (Mask.) 



Cerarian spines close together in all the cerarii, dorsal 



body setae slender or at least not short and conical .... 6 



6. With a large, well defined, chitinized area surround- 



ing the anal lobe cerarii . . . timberlakei (Ckll.) 



