PITYOPHTHORUS. 235 
ventral segment is more or less excised subcircularly, the pygidium being declivous, 
more or less reflexed, and visible from below. This, on careful examination, appears 
to be a constant character, more evident in some species than in others; but the degree 
to which it occurs cannot be sufficiently defined to be of use in differentiation. 
~The majority of the species are conifer-feeders, but in North America certain kinds 
have been found to breed in Quercus, Liquidambar, and Khus. 
Leconte included in Pityophthorus the N.-American species of Gnathotrichus and 
Pityogenes. These have since been excluded by American entomologists, but the 
genus thus restricted appears yet to be capable of further division. 
In those species with lineato-punctate elytra belonging to Leconte’s group C of 
which the sexes have been examined by Eichhoff and Hopkins, the presence of a frontal 
tuft is a female character, while in the species of Leconte’s group B, with confusedly- 
punctured and pubescent elytra, Hopkins has shown for P. minutissimus (Zimm.) (Canad. 
Ent. xxvi. p. 277) that the frontal tuft isa male character. It is hard to suppose that 
opposite sexual characters coexist in the same genus. 
It is probable that the species here collected under the generic name will be 
separable into two or more genera, if and when their structural characters can be more 
exhaustively studied. 
1. Antennal club narrow, with straight or nearly straight sutures . . . 2. 
Antennal club broad-oval or suborbicular, with curved sutures . . . 1d. 
2. Elytra punctured in rows . 3. 
Elytra confusedly punctured . - ee woe eee pubipennis, Lee. 
3. Elytral declivity impressed, at least on each side of the suture . . . 4. 
Declivity uniformly convex, the sutural margins at most feebly raised . 1 
4, Elytra acuminateat apex. 6 6-1 ee ee eee es 5 
Elytra conjointly rounded at apex . . o 2 eo 6 . 9 
5. Elytral declivity with a deep common sulcus, the margins of the suture 
less elevated than the lateral calli . . 2. 2 2. + + e+ +) migricans, sp. n. 
Declivity with a shailow sulcus on each side of the suture, its margins 
on a level with the lateralcali. . . . Loe . . . 6. 
6. Second row of punctures on the elytra absolutely regular throughout . amenus, sp. n. 
Second row with at least two punctures displaced opposite punctures of 
the third interstice . . 2... ee ee ee ee 
7. All the inner rows of punctures on the elytra irregular, non-striate . . confusus, sp. n, 
The first and third rows regular, feebly impressed . . . . . . . 8. 
8. Form rather stout; prothorax ample, not depressed behind . . . . poricollis, sp. n. 
Form rather slender; prothorax not ample, slightly depressed behind the 
discal elevation cacuminatus, sp. un. 
9, Apical half of the prothorax confusedly ¢ granulate. . . . . . .- . 10. 
Apical half of the prothorax with concentric lines of granules. . . . II. 
10. Elytral interstices subconvex throughout . . . . . . . - + «+ guatemalensis, sp. n. 
Elytral interstices quite flat before the middle . . . . . . . . » diglyphus, sp. n. 
2HH 2 
