506 REVISION OF THE ELATERIDiE 



Of the species described in this essay, D. mancus and D. pubescens differ from the 

 others in having the mouth entirely closed by the sternum, and in tins respect agree 

 with Agriotes segetis of Europe. The basal fissures are more elongated than in the other 

 species, and present in certain lights the appearance of elevated lines: it might be doubted 

 which of the two is the real El. mancus Say, but as it is compared with El. convexus, evi- 

 dently a robust species of Cardiophorus, I have given the preference to that having the 

 more robust form. 



D. pauper, D. subustus, D. bigcminatus, D. oblongicollis, D. isabellinus, and D. avulsus, 

 agree closely in characters with the European D. marginatus, which is the type of Esch- 

 scholtz's genus Dolopius: in them the posterior coxa? are somewhat suddenly dilated in- 

 ternally ; in the remaining species the coxa} are hardly wider internally, and the second 

 and third joints of the antenna} are variable in their proportions: united together, they are 

 longer than the fourth; they are equal in size, or nearly so; but in D. limosus the second 

 appears distinctly longer than the third; the suture of the prosternum is more or less ex- 

 cavated anteriorly, and in all of them to a greater extent than in the European D. margi- 

 natus. 



Under these circumstances, I did not feel justified in separating such closely allied spe- 

 cies into different genera, though I confess that the following arrangement of the species 

 described would be more natural than the one proposed in the text, although the thickened 

 and emarginate mandibles separate A. mancus from all the other species, both native and 

 foreign, that I have examined : 



A. Sternum subtus os omnino obtegens: A. mancus and pubescens. 



B. Os subtus plus minusve liberum : 



Co-xce posticre intus vix latiores: A. collaris, fucosus, sordidus. 



Coxte posticfe intus modice, subgradatim angustatte : A. avulsus, sordidus, stabilis, limosus. 



Coxpe posticre intus modice fere subito angustatse : 



Antenna; articulis 2 et 3 coniunctis 4'" brevioribus : A. isabellinus and oblongicollis. 



Antennre articulis 2 et 3 coniunctis 4 t0 longioribus, (frons apice subangulata:) A. pauper, 

 subustus, bigeminatus. 



The following note from Dr. Harris will explain the different views taken by us of the 

 nomenclature of the species, considered by Dr. Harris as El. obesus, and by me as Elater 

 mancus. 



"The species which Dr. Le Conte refers to Mater mancus of Say, is strictly congerical with the 

 European species segetis Gyll. (striatus Fabr.) variabilis F., and sputator F., with all of which it has 

 been carefully compared. These species belong to the genus Agriotes of Eschscholtz and of La- 

 treille. The insect in question is to be found in the 'Catalogue of the insects of Massachusetts,' ap- 

 pended to the 2d edition of Hitchcock's Report, under the name E. pumilus, with the doubtful syno- 

 nym, 'obesus? var. S.,' given on the authority of Mr. Say: and it is described as Elater (Agriotes) 

 obesus in the 'Treatise on Insects Injurious to Vegetation,' in which the specific name was adopted in 

 deference to Mr. Say, although the writer was previously aware that the insect did not accord with 

 Mr. Say's description of the obesus." 



The following species of this family are unknown to me; those described from Russian 



