220 Miss A. L. Emblcton on the 



very serious ravages of a variety of scales including the 

 " pernicious," or San Jose scale (Asjndiotus perniciosus). 



The history of the work done in this subject was surn- 

 marizeil last year by Mr. R. Newstead,* and, in speak- 

 ing of the contributions which liavc come from this 

 country, he says : " Up to the year 1887 the English works 

 were fragmentary and most inaccurate, but at that time 

 Mr, J. W. Douglas began a series of articles on British and 

 Foreign C'occidcV,int\ie "Entomologist's Monthly Mngazinc," 

 which he continued till the year 1894, when he then com- 

 pleted his twenty-seventh article. Needless to add, these 

 were very thorough, and contain a vast amount of valuable 

 information to the student of the British CoccicLv." In 1891 

 Mr. Newstead began to publish his own work on the sub- 

 ject, and he has continued to do so up to the present time, 

 the first volume of his monogra2:)h on British Coccid/B 

 having only just been issued. 



Although many of the species of Coccidx have now 

 been described and figured, our knowledge at present of 

 the life-histories, parasites and all their varied biological 

 aspects and relations is very limited ; unfortunately, too, 

 the knowledge that does exist is scattered and disconnected, 

 so that it is of little help to the horticulturist, to whom 

 the chief consideration is how to control these pests. For 

 success in this matter it is of the first impoitance that the 

 life-histories of the creatures should be thoroughly well 

 known, and that the modes by which they are kept in 

 check in a state of nature should be ascertained. 



The insect enemies of scales are usually called "para- 

 sites " ; but the term is ambiguous, for there arc two 

 distinct kinds : (i.) The predaceous enemies which roam 

 about freely and (levour the scales, and which it would be 

 well to speak of as " predators" ; (ii.) the true parasites, 

 the best known of whicli are small Hymenopterous flies, 

 whose growth and development take place inside the 

 Coccidm. In this way the pests may be actually exter- 

 minated, while at tlie same time there is little or no 

 external evidence of what is occurring. The term 

 " parasite " should bo restricted to these internal 

 destroyers. 



The predaceous enemies of Coccidiu have received more 

 attention than their internal parasites, and they have been 



* '' Oil the progress in the study of Coccidae." Ent. Rcc, xiii, 1901, 

 pp. 57-59. 



