April, '15] 



QUAYLE: THE CITRICOLA SCALE 



291 



Their presence was not noticed until after the worms had reached the 

 height of their abundance, but during the last week in June the white 

 cocoons of the hymenopterons and the blackened and putrid bodies 

 of worms killed by disease were to be seen everywhere in the infested 

 territory. * 



In the Bureau of" Entomology bulletin 95, Part YH, the author, 

 Mr. James A. Hyslop, makes the following statement: ''The alfalfa 

 looper has been held in check by a number of parasites and a disease 

 . . . . The time may come, however, when these natural enemies 

 may themselves suffer reverses and temporarily fail to hold the pest 

 in check." Mr. Hyslop's prediction has certainly come true and the 

 wisdom of collecting and publishing biological data concerning insects 

 that are not of immediate economic importance is again emphasized. 



THE CITRICOLA SCALE 



{Coccus citricola, Camp.) 

 By H. J. QuAYLE, Citrus Experiment Station, Riverside, California 



Six or seven years ago some of the horticultural officers of southern 

 California, particularly Mr. Cundiff and Mr. Pease, horticultural com- 

 missioners of Riverside and San Bernardino Counties, had observed 

 cases where fumigation was not effective against what was supposed 

 to be the soft brown scale {Coccus hesperidum) . In these cases, too^ 

 the scale was generall}^ distributed over the old trees in the grove, while 

 usually the soft brown scale occurs more commonly on young trees 

 or a few twigs or branches of older trees. Some specimens of what was 

 supposed to be this new variety of scale were at the time sent to the 

 Bureau of Entomology as well as to the writer. The scales were iden- 

 tified in both cases as C. hesperidum. But further general observations 

 showed that the scale in question was very sparingly attacked by 

 parasites, and that ants were not attracted to it in large numbers, both 

 points being the reverse of what is true for C. hesperidum. At about 

 the same timie this variety was discovered at Claremont, and it was 

 identified by Mr. Essig as Coccus longulus and later as C. elongatus. 

 When an incidental study of this scale was started by the writer in, 

 1911, it did not appear to agree positively with any of the species that 

 it had previously been placed under. In 1913 Mr. Roy E. Campbell 

 was engaged as an assistant to work particularly on this scale, and as 

 a result of these studies, it was determined as a new species and was 

 given the name of Coccus citricola.'^ 



This scale is now known to occur over widely separated localities 

 in California and attacks citrus trees primarily. It has been found also 



1 A New Coccid Infesting Citrus Trees in California. By Roy E. Campbell, En- 

 tomological News, Vol. XXV, May, 1914. 



