16 



THE CALIFORNIA SPECIES OF MEALY BUGS 



graph did he not already know them to be distinct, or, knowing them to 

 be distinct, where he would draw the line between them. 



Fig. 6. Pseudococcus cltri (Risso) ; antennal graph drawn from specimens taken 



from citrus. 



Fig. 7. Pseudococcus citrophilus Claussen; antennal graphs drawn from speci- 

 mens taken from citrus and other hosts. 



In text figures 5 to 8 are shown the graphs of the four species, 

 Pseudococcus longispinus (Targ.), P. citri (Risso), P. citrophilus 

 (Claussen) and P. maritimus (Ehrhorn). All four of these species occur 

 on citrus, as well as on many other hosts, in California. They are readily 

 separable in life and structurally are very different and very easily recog- 

 nizable. Yet the graphs of the first three fall almost entirely within the 

 graph of P. maritimus nor is there sufficient difference between any of 



