47 
pubescence short and suberect, conforming to the colour of the elytral 
bands; the basal margin, the scutellum, the suture, and three transverse 
bands black, the intervening bands yellow, the bands subequal in width; 
the 1st band subbasal, yellow, from the side margin nearly to the sutural 
margin; 2nd, antemedian, black, from the side margin to the suture; 3rd, 
median, yellow, from the side margin nearly to the suture; 5th, anteapical, 
yellow, from the side margin nearly to the suture; 6th, apical, black; the 
antennae feebly thickened apically, attaining the middle of the elytra. 
One paratype, “Wyoming,” agrees in colour with the type except 
that the yellow bands on the elytra are much narrower; one, “W. Terr.,” 
has the legs and abdomen black; one, “Wyoming,” has the last segment of 
the abdomen reddish. The median yellow band is angulate near the middle 
of the front margin and arcuate on the hind margin in all four specimens. 
The length varies from 7 to 9 mm. The male has the last ventral segment 
flattened at the apex. 
Holotype, 9 , Yellowstone National park, VI-28-12, R. C. Osborn. 
In the Canadian National collection, Ottawa. 
Paratypes, W. Terr.; cf, Yellowstone park, Wyom.; 9, Yellow- 
stone park., Wyom., the last in the collection of Mr. J. N. Knull, 
Harrisburg, Pa., for whom the species is named. 
(7) Anoplodera instabilis Hald., 1847, Trans. Am. Phil. Soc,, vol. X, p. 59. 
convexa Lee., 1850, Jour. Phila. Acad. Sci., 2, vol. 1, p. 332. 
vivarium Csy., 1924, Mem. on the Coleop., vol. XI, p. 282. 
pacifica Csy., 1913, Mem. on the Coleop., p. 249, (cf). 
trajecta Csy., 1913, Mem. on the Coleop., p. 250, (cf). 
gaurotoides Csy., 1893, Ann. N.Y. Acad. Sci., vol. VII, 
p, 592, (9). 
Length 6 to 12 mm. Anoplodera instabilis presents a remarkable 
variation in size and in coloration. The general scheme of coloration 
in this species is black, with the elytra testaceous and marked with four, 
transverse, black bands, namely: a narrow basal band, a postbasal band 
at the basal third, a postmedian band immediately behind the middle, and 
an apical band across the apices. The apical band is entire in all our 
specimens; the median band is variably reduced to a transverse, rounded, 
lateral patch or spot; the postbasal band is commonly reduced to a diskal 
and a lateral spot, the diskal spot in some cases being obsolete and the 
lateral spot evanescent. The black form has been seen from North West 
Territories, Manitoba, Alberta, and Arizona, and a series from California 
is before us in which the black predominates on the elytra, reducing the 
yellow colour to spots. The spots are in some cases fused along the middle 
of each elytron so that the markings are more or less distinctly longitudinal. 
Two specimens from Algonquin Park, Ont., have the elytra with red 
spots. Some black specimens have rufous abdominal segments. Many 
paired specimens are before us showing great variation in size and macula- 
tion in the same pair, and indicating that these colour forms are not even 
races, but individual variations of the same species, instabilis Hald. 
The last ventral is rounded in the male, truncate-emarginate and flat- 
tened in the female. The first segment of the hind tarsus is densely hairy 
beneath. The pubescence of the pronotum is usually longer on the males 
than on the females. 
61136—41 
