THK CANADIAN ENTOMOLOGIST. 17 



A NEW PARASITE OF THE HARLEQUIN CABBAGE BUG. 



BY L. O. HOWARD, WASHINGTON, D. C. 



The great damage which has been done to cabbage and other crucif- 

 erous plants by the harlequin cabbage bug ( Murgantia histrionica) in 

 its spread towards the north-east renders of interest any comments upon 

 its natural checks. Professor H. A. Morgan, of the Louisiana Agricultural 

 Experiment Station at Baton Rouge, has reared in considerable numbers 

 a Proctotrypid parasite from the eggs of this destructive insect, which 

 was named by Mr. Ashmead Trissoicus niurgantm. With commendable 

 enterprise, Professor Morgan has sent eggs of the cabbage bug to various 

 Experiment Station Entomologists situated in localities which the Mur- 

 gantia has more or less recently invaded, and to which it seems probable 

 that the parasite has not yet followed it. Professor Webster, of Ohio, has 

 announced that he is trying to introduce this beneficial insect, and Pro- 

 fessor Johnson, of Maryland, is making the same effort with Professor 

 Morgan's help. 



As preliminary to this introduction experiment, Professor Johnson 

 has made an effort to ascertain whether Murgantia histrionica is already 

 jiarasitized in its egg condition in Maryland. In the course of this effort 

 he has bred several specimens of a Chalcidid parasite which he has asked 

 the writer to name. Examination shows this insect to belong to the genus 

 Encyrtus. It is interesting to note that no Encyrtina? are known in 

 Europe to live in heieropterous eggs. In this country, however, several 

 species probably have this habit. Mr. Ashmead has reared a species fron:> 

 the eggs of Anasa tristis, in Florida, and in the Insectary of the Depart- 

 ment of Agriculture at Washington species have been reared from the 

 eggs of Prionidus cristatus, received from Texas, and from the eggs of an 

 unknown heteropterous insect found upon pine in California. The species 

 reared by Professor Johnson differs from any of these. It is very closely 

 related to Encyrtus mitratus, Dalman, of Europe, the host relations of 

 which are not known. The specimens in collections have been captured. 

 It may ultimately prove to have been reared from heteropterous eggs. 



As unsatisfactory as it is to describe isolated species, it is sometimes 

 desirable, as in this instance. The parasite has some importance, and 

 Professor Johnson wishes to refer to it definitely by name. The following 

 description is therefore submitted : 



