THE COCCIDAE OF CALIFORNIA, 



By EDWARD K. CARNES. 



About sixteen years ago the State Board of Horticulture published a 

 list of the Coccidse (scale insects) of California, giving some twenty- 

 species found in the State. At that time comparatively little was 

 known, by the residents of the State, about scale bugs or the amount of 

 injury that could be caused by them; yet, to-day, there is no other 

 single family of insects that is as important to the horticulturists of the 

 world as are these minute creatures, and we can not know too much 

 about them. 



As a group they are very unattractive to the average entomologist, 

 and even more so to the average horticulturist, yet a knowledge of the 

 species and the best known methods of combating their attacks is a 

 very essential part of the education of every' successful fruit-grower. 

 Fruit-growing is a competitive business, and the successful grower must 

 avail himself of every opportunity to gain knowledge that will be of 

 assistance to him in his business; therefore, it has been deemed advis- 

 able to bring before his notice the following list of species occurring in 

 California, with illustrations and short descriptions of the more impor- 

 tant varieties, in order to enable the grower to recognize and distinguish 

 between the destructive species and those that are not so destructive. 

 Since the first list was published, and especially during the last few 

 years, there has been a very active period among the growers, orchard- 

 ists, nurserymen, and those having greenhouse interests, to gain a knowl- 

 edge of "scale insects." This activity has not been prompted by a love 

 of the study of this particular branch of entomology, but purely as a 

 business proposition, for these seemingly insignificant insects are capa- 

 ble of causing an enormous loss to the orchard, vineyard, nursery, or 

 field in which they have gained a foothold. It must be remembered 

 that each scale insect, after it has settled on the trunk, branch, or leaf 

 of its particular host plant, virtually turns itself into an automatic 

 pump and extracts the sap which is so vital to the life and growth of 

 the tree. Usually the damage is done before the infestation is discov- 

 ered, as many of our growers are absolutely without the slightest 

 knowledge of scale insects. A tree, plant, or shrub will put forth every 

 effort to sustain itself against the attack of the insect and will not show 

 any immediate damage from the insects at work upon it, but even the 

 strongest tree must ultimately yield to the persistent pumping of its life 

 sap by the enormous number engaged in the work, and will iiuddenly 



