271 



Eiistoni region from New York to Louisiana and Illinois. The 

 labrum is very broadly and feebly trilobcd, the middle lobe wider 

 than the side ones. The hind tibia and tarsi are longer and more 

 slender than in the following species; the joints of the antennae 

 2-4 are strongly compressed and carinate ; the mandiljles are feebly 

 (var. loevis), or not at all striate; the tooth of the mentum is deeply 

 concave, and seems almost emarginate. 



Till' specimens from the Southern States are frequently without 

 the blue margin, and are of a more dull color than those from the 

 north. Dr. Zimmermann believed that they indicated a distinct 

 species, to which he gave the name morio, adopted, in my synopsis 

 above cited; the description of Fabricius does not mention a blue 

 margin, and it is possible, therefore, that his type should be refer- 

 red rather to the race mor-io, than to the usual form which is 

 described by Say and Dejean.* The female is dull, the male shining. 



7. P. duplicatus, Lee, Trans. Am. Phil. Soc, X., 395. 



var. P. costifer, Lee. Proc. Ac. Nat. Sc. Phila., 1854, 79 ; Journ. Ac. 

 Phila., 2d, IV., 15, pi. IV., f. 11. 



Texas, northward to Indian Territory. This and the next species 

 are nearly related, and differ by the arrangement of the striae of 

 the elytra, which in this are represented by rows of punctures ap- 

 proximated by pairs, but in ohsoletus by equally distant rows ; in 

 the best marked specimens the alternate interspaces towards the 

 sides are elevated, forming ridges, with broad intervening grooves; 

 sometimes these ridges and grooves disappear, and even the rows of 

 punctures cannot be seen, and only the outermost of the ridges 

 remain ; this is the variety which I named costifer. The labrum is 

 distinctly trilobed, the middle lobe advanced, and rounded, not 

 wider than the side lobes, which are subacute and sinuate exter- 

 nally; the mandibles are very feebly striate; antennae as in the 

 preceding; hind tibiae and tarsi alike in both sexes. 



In one specimen from Arizona even the sub-marginal costa has 

 become obsolete, marked only by a very feeble marginal furrow. 



* Dr. Zimmermann recognized this foct after tlie publication of my sj'nopsis, but still viewing 

 the two forms as distinct species, called the one with a blue margin P. limhatus, with the fol- 

 lowing reniiirks, which I translate from his MS.: "Of precisely the same form as depressus, 

 also with smooth mandibles, and slender hind tarsi, which are longer than the tibiae; but 

 usually somewhat smaller, proportionally narrow er. more convex, and with the humeral carina 

 a little shorter : shining black, with the sides of the prolhorax and elytra blue or violet. 



