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REVISION OF THE TENEBRMIDD OF AMERICA, 



NORTH OF MEXICO. 

 By GEO. H. HORN, M. D. 



The object of the following pages is two-fold — first, to afford a proper means of making 

 known to science the results of four years field work in California and adjacent regions; 

 and secondly, to bring before the student of our fauna as nearly a correct list with syno- 

 nymy of all our species as possible, witli short descriptions and synoptic tables, whereby 

 all our known species can be readily recognised, rendering it necessary to refer only 

 doubtful or new ones to those having typical collections for proper comparison. 



The Tenebrionida? commence a large series of coleopterous insects, of which the he- 

 tcromerous tarsi constitute the most important as well as the most constant character; 

 and although occupying such an important position in this Section of the great Order 

 Coleoptera, it is neither peculiar, nor without exception. 



In the family Trictenotomida?, as well as in Silphidae Staphylinida? and Colyduda?, 

 we have instances of heteromerous tarsi, although in some instances the character is re- 

 versed, that is, the anterior tarsi are four jointed instead of the hind tarsi. Two species 

 of Heteromera are said to have pentamerous tarsi (Tanyrhinus singularis Mann., and Se- 

 pidium pradieri Guerin.) and one genus, Heterotarsus, has the number of joints reduced 

 by one in each tarsus, so that the anterior and middle tarsi are tetramerous, while the 

 hind tarsi are trimerous. 



The following characters are those which define all the genera and species known to 

 me of the family Tenebrionidee. 



Prosternum attaining the hind margin of the thorax, epimera never contiguous on the 

 median, line. Anterior coxal cavities closed behind. Tarsi Iteteromerous, penultimate joint 

 never spongy beneath. Tarsal claws simple. First three joints of the abdomen connate. 

 Elytra with distinct epipleurev. 



Any heteromerous Coleopteron not possessing all of the above characters, must be re- 

 ferred to some other family. C'ossyphus has the epimera of the presternum contiguous 

 along the median line, and the presternum not attaining the hind margin of the prothorax, 

 and must constitute a family apart and be placed at the head of that large primary division 

 of the Order in which this peculiar formation of presternum is always found, called by Dr. 

 Leconte the Ithynchophora. 



Even to the present time, many European entomologists persist in retaining Boros and 



AMERI. PHILOSO. SOC. — VOL. XIV. — G4 



