THE CANADIAN ENTOMOLOGIST 171 



percent of the plants were injured to some degree. At harvest time one hundred 

 normal plants and an equal number of plants attacked by the insect were threshed. 

 The amounts of seed secured, both before and after cleaning, are given in the fol- 

 lowing table : 



One hundred I Weight of seed 

 plants each before cleaning 



Not infested 



Infested 



Loss due to insect 



109.2 oz. 

 74.3 oz. 



Weight of seed 

 after cleaning 



97.4 oz. 



64. 5 oz. 



32.6 oz. 



Percent of seed lost 

 in cleaning 



11 

 13 



Plants not attacked by the insect therefore yielded practically thirty-three 

 and one-half per cent, more seed than the attacked plants. Since there were 

 forty-seven per cent, of the plants attacked by the insect the loss would be sixteen 

 per cent of the crop. The seed yield was approximately two hundred and fifty 

 pounds per acre this year, and consequently the loss occasioned by the weevil was 

 forty pounds per acre valued at fifty dollars (1920). Even greater losses have 

 doubtless occurred since a cabbage seed contractor and some growers have cited 

 instances where in previous years this insect has occasioned the loss of entire 

 crops. 



NEW SPECIES OF SYRPHIDAE (DIPTERA) 



BY C. HOWARD CURRAN, 

 Orillia, Ont. 



Syrplius invigorus, new species. 



Eyes bare ; face yellow, cheeks and oral margin black ; no facial stripe ; 

 first and third abdominal bands interrupted, the second entire. Length 10-11 

 mm. 



Male. Face and sides of front reddish yellow ; cheeks, oral margin and 

 sides of the face, reaching to the tubercle, brownish black, posterior oral border 

 reddish yellow ; face finely white pilose and more or less whitish pubescent ; 

 tubercle rather large, the epistoma not at all pro'duced ; front black in the middle; 

 frontal pile yellowish or sometimes brownish, of the vertex, black, of posterior 

 orbits, white; eyes bare. Antennae reddish yellow or orange, more or less 

 brownish above; arista reddish brown. 



Thorax shining greenish black, with pallid yellowish white pile, more 

 "''llnw along the lateral margins before the suture, and almost white on thr 

 pleurae. Scutellum translucent pale yellowish brown the base and sides black ; 

 pile whitish. 



Abdomen opaque black, the first segment and complete borders of the 

 following segments, the lateral margins more narrowly, shining black, sometimes 

 with a greenish tinge. Second segment with a large triangular spot in the 

 middle on each side; third segment with an abbreviated yellow band moderately 

 separated from the anterior margin, deeply incised posteriorly ( about half 

 through) and usually with a small triangular projection in the middle anteriorly; 

 the band is broadest laterally and is narrowly separated from the lateral mar- 

 gins. Band on fourth segment similar, but moderately interrupted in the middle, 

 the inner ends of the spots formed being almost evenly rounded posteriorly to 

 the lateral fourth ; apex of third .-regment in the middle and base of fourth at 

 the sides, narrowly yellow ; apex of fourth segment and triangles on the basal 



