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Aug. F. Foerste 
equalling the width of the border, the two together equalling about 
four-fifths of a millimeter. 
The axial lobe of the thorax has a width of fully 3.5 mm., nar- 
rowing to 2.5 mm. at the anterior end of the pygidium. 
The number of pleural segments is ten. A median groove 
follows the lateral lobes of these segments laterally to the point 
where they curve posteriorly. The length of this posteriorly 
directed part is approximately between 1 and 1.5 mm. 
Axial lobe of pygidium distinctly defined posteriorly as well as 
laterally. Its length is 2.8 mm. in a pygidium whose length is 
3.8 mm., the flattened marginal border of the pygidium having a 
width of 1 mm. Essentially the same width of border is shown 
posteriorly by pygidia which have a length of nearly 5 mm. 
The anterior annulation of the axial lobe of the pygidium, which 
is in contact with the thorax, is relatively narrow but strongly 
defined. The second annulation is the first one fully exposed, and 
is always very distinct. It is followed by one fairly distinct an- 
nulation, three much less distinct annulations, and rarely by 
another scarcely perceptible annulation, the last being followed 
by a space having room for two more annulations, where, how- 
ever, none are present. 
On the lateral lobes of the pygidium, the anterior pleural seg- 
ment, adjoining the pleural segments of the thorax is strongly 
marked posteriorly. The next pleural segment is the first one 
fully exposed; this is fairly distinct, and has an indication of a 
median groove. This is followed by two much less distinct indi- 
cations of pleural segments with no trace of a median groove, fol- 
lowed by another, scarcely perceptible pleural segment. The 
first fully exposed pleural segment extends across the flattened 
border of the pygidium. The remainder scarcely affect the 
border. The flattened border of the pygidium is relatively broad 
and slightly concave. 
The specimens here described were obtained at Chambly Can- 
ton, on the southern side of the Richelieu River, a short distance 
below the dam. It occurs also at several localities east of Ottawa, 
among these: about a mile northwest of Hawthorne station; also 
along the road reached by going three quarters of a mile west of 
Vars, along the railroad, and then from half a mile to a little more 
than a mile northwestward along the public road. Along the 
Nicolet River, southwest of Ste. Monique, Proetus ranges from 
