22 THE CALIFORNIA SPECIES OF MEALY BUGS 



and slender setae. This type, however, is subject to much modification. 

 In some cases the cerarian spines are quite large and stout and are readily 

 distinguishable from the body setae, while in others they are recogniz- 

 able only by their paired character and position. In some cases the 

 grouped pores are very numerous, in others entirely lacking. In some 

 species the cerarian spines are accompanied by a group of slender setae, 

 which I designate as "auxiliary setae," while in others these are not pres- 

 ent. In some more than two spines are present in part or even all of the 

 cerarii. 



In certain instances a part or even all of the cerarii are surrounded 

 by more or less well defined chitinized areas which it is usually difficult 

 or even impossible to see in unstained preparations. In the genus Puto, 

 and in certain exotic species at present referred to Phenacoccus, all the 

 cerarii are thus surrounded but in general these areas are to be found 

 only in connection with the last one or more abdominal pairs. The size 

 and shape of these areas are in some cases extremely constant and of 

 much assistance in recognizing species. I am not aware that these have 

 previously been noted except in connection with the genus Puto. 



The number of pairs of cerarii ranges from none to as many as 24. 

 Within certain limits the number may be taken as of generic value, 

 although it is probably not always so. I have seen no species of Phena- 

 coccus (except certain exotic forms now referred here, but which I am 

 convinced are generically distinct) in which there are less than 18 pairs, 

 and no species of Pseudococcus in which there are more than 17, although 

 in some species there are less. In Trionymus the number is from one to 

 four, while in Antonina there are none. While I have made use of these 

 facts in this paper the matter needs to be much more fully investigated 

 before any extensive generalizations can be made. 



Anal Lobes. The form of the anal lobes is in general not such as to 

 be usable for taxonomic purposes, chiefly because of the difficulty experi- 

 enced in obtaining preparations of a uniform type. In some cases they 

 are quite prominent and in others practically lacking, but unless the 

 characters displayed are of an extreme nature it is hardly possible to 

 make use of them. 



In certain species a more or less well defined chitinized area occurs 

 on the ventral side of each anal lobe, usually extending in from the base 

 of the anal lobe seta. In some species these areas are sufficiently con- 

 stant in shape and size to be extremely useful characters, although in 

 others where they are normally very small, they may vary even to the 

 point of being entirely lacking and hence may not be relied upon. 



