140 THE CANADIAN ENTOMOLOGIST 



tifications in the Canadian National Collection. Tt soon was evident that in the 

 affinis group, which is essentially a northern one, there were a number of closely 

 allied forms. capal)le a])parently of separation on structural details of palpi, an- 

 tennae, etc., which heretofore had been lum])cd under a sinc^le specific name. 



In anticipation of a more extended work on the entire genus and with a 

 view to clearing up the various nomenclatorial tangles in the group, 1 offer the 

 following notes on the various Canadian species, accompanied by a key, based 

 on a study of the structural characters of the females only. Owing to the re- 

 lative scarcity of the males and the difficulty of definitely associating them with 

 the correct females I am unable at the present time to give satisfactory char- 

 acters for this sex. I have been in constant correspondence with Prof. J as. Mine 

 in regard to the correct application of many of our older names and I am pleased 

 to state that in every instance we agree as to the species to which such names 

 should be applied. Miss G. Ricardo has also compared for. me a good deal of 

 material with Walker's types in the British Museum and thus enabled me to 

 definitely place several of his heretofore unrecognized species. To both these 

 workers my hearty thanks is due. I am also greatly indebted to Mr. E. P. Van- 

 duzee. San Francisco, Calif., Prof. A. L. Lovett, Corvallis, Oreg., Prof. R. A. 

 Cooley, Bozeman, Mont, and Mr. J. B. Wallis, Winnipeg. Man. for loan of mat- 

 erial. 



The affinis^ group, as understood in the present paper, comprises those 

 species in which the greater part of the first four abdominal segments is red or 

 orange-red of various shades with a varyingly broad blackish dorsal band. 

 The species extend across the entire northern half of the American continent 

 reaching southward along the Atlantic Coast, down the Rocky Mountains and 

 through the Cascades to the Sierra Nevada Mts. Further collection, especially 

 in British Columbia will probably increase the number of known species; at the 

 present time I am able to differentiate thirteen species. 



Key to Species. 



FEMALES. 



1. Abdomen with 1st segment laterally orange or reddish 2 



Abdomen with 1st segment laterally black 12 



2. Wings with all cross-veins distinctly ciouded with brown 



lasioplitlialiini.-; Macq. 



Wings unclouded or with only bifurcation of tliird vein clouded 3 



3. Palpi thin, not swollen at base of 2nd joint 4 



Palpi .shorter, with base of 2nd joint noticeably thickened 9 



4. Subcallus normally denuded; front very broad captonis Mart. 



Subcallus normally not denuded 5 



5. Small species, 10 mm., very thin ])al])i, antennae with ord joint scarcely 



excavated basally minusculus Hine. 



Larger species, 14mm., or over 6 



6. Large species, 17-I9nim; antennae with 3r(l joint very strongly excavated 



basally 7 



Smaller species, 14-17mm; antennae only moderately excavated at base. .8 



7. Palpi deep orange-yellow; abdomen laterally deep orange-red. .a///H/j- Kby 



