June-Sept., 19,9.] DAVIS : ClCADAS. 185 



clouded each side with reddish ; tergum 

 black with much tomentum, which when 

 removed leaves a smooth surface. A black 

 species with the usual four orange spots 

 before the mesonotal X, and orange mem- 

 branes at the base of both pairs of wings. 

 Expands about 62 mm. 



canadensis (Provancher) 

 \ enation about as in canadensis, but the 

 veins not thickened. Pronotum generally 

 all black, but sometimes mottled with dull 

 red each side of the center. Further dis- 

 tinguished from the other two species in 

 this section by having the abdomen be- 

 neath centrally pale. Expands about 70 mm. 

 tristis Van D. 

 CC. Base of the fore and hind wings not of the usual orange red 

 variegated with black. 

 Color rufo-ferruginous including the venation of fore and 

 hind wings, with a few marks on the vertex and a dorsal 

 vitta on the tergum black. Expands about 70 mm. 



arctostaphyla? Van D. 



Body almost entirely black; basal cell of the fore wings 



clear ; membranes at base of both pairs of wings whitish. 



Expands about 65 mm canescens Van D. 



Body and wing venation nearly entirely green : basal cell of 



fore wings clear. Expands 65 mm viridis Davis 



Body and wing venation nearly entirely orange; basal cell 

 of fore wings clear; a black band between the eyes, and 

 a conspicuous dorsal band of the same color extending 

 from the hind margin of the pronotum to the end of the 



abdomen. Expands about 55 mm aurantiaca Davis 



BB. Expanse of fore wings 50 mm. or less ; orange variegated with black 

 at base of both pairs of wings. (Some examples of fratercula 

 exceed 50 mm.) 

 G. Pronotum in mature individuals black centrally margined with 

 orange especially behind. In triangulata the grooves of 

 the pronotum are sometimes orange colored. 

 Basal cell of fore wings darkly opaque, abdomen black be- 

 neath with hind margins of segments reddish. A dark- 

 colored species. Expands about 47 mm. fratercula Davis 

 Basal cell and venation of fore wings yellowish ; abdomen 

 yellowish beneath with numerous silken hairs ; front of 

 head and eyes not prominent. Expands about 50 mm. 



oregona Davis 

 Basal cell of fore wings translucent ; abdomen yellowish be- 



