NORTH AMERICAN COLEOPTERA. 
8 
2. — Tibife stouter than usual, the outer side beset with short spinules, the spurs 
very distinct Group LITTORALIS. 
Tibiffi slender, not spinulose externally, the spurs usually very small and 
indistinct. 
Depressed opaque species, thorax coarsely and closely punctate. 
Group SQUALIDUS. 
More or less convex and shining, thorax variably punctate, but never 
opaque, the median line more or less impressed. 
Hind angles of thorax slender and divergent, the basal incisure well 
marked; surface not distinctly pubescent.. -Group HYPERBOREUS. 
Hind angles of thorax stouter, scarcely at all divergent, basal incisures 
feeble; surface pubescent Group ABBREVIATUS. 
3. — Elytra with the striae entirely, or in great part obliterated ; in the latter 
case, those near the suture alone evident Group PECTORALIS. 
Elytra with all the striae entire 4. 
4. — Depressed species, dorsum quite flat, surface opaque, densely punctulate 
and pubescent; hind angles of thorax with short carina. 
Group STRIATULUS. 
Convex species. 
Thorax coarsely granulate, usually with a smooth elevated median line. 
/ Group CHORIS. 
Thorax unequally sculptured, either subasperate or more densely, coarsely 
punctate near apex, posteriorly smoother, median line usually smooth 
Group MELSHEIMERI. 
Thorax equally punctate, either sparsely or moderately closely ; elytra 
ornate Group PERPLEXUS. 
The groups which follow are arranged in a manner to show what 
seems to be a natural sequence based on facies. 
In conclusion, I wish to acknowledge my indebtedness to Dr. 
Hamilton and Mr. Ulke for the loan and gift of specimens, and to 
Mr. Blanchard for first having called my attention to the pubescent 
spot in the abdomen of gradarms, thereby suggesting a new line of 
investigation which has resulted profitably. 
Group LITTORALIS. 
Prosternal sutures straight, very nearly parallel. Maxillary palpi 
moderate in length, the last joint elongate oval, obliquely truncate 
at apex. Tibiae shorter than usual, the outer edge beset with short 
spinules, the terminal spurs well marked. Form robust, body ap- 
terous. 
This group contains but one species so unlike those which follow, 
as to lead to the supposition that it should be more completely sepa- 
rated. There are, however, no differences of sufficient importance 
to warrant generic separation. 
