Of this remarkable species there is a male specimen in my own 

 collection from the Huachuca Mts., Arizona. Two examples (c?$) in 

 the Sherman collection, and a third example in the Roberts collection, 

 all from the Organ Mts., New Mexico, agree in all essential characters, 

 but vary in having the surface feebly aenescent, the elytra each with a 

 vague longitudinal sulcus between the rows of coarser discal punctures, 

 the latter being more distinct than in my specimen and the prosternal 

 process flat or a little impressed and more or less rugose at its broadest 

 part. 



This small opaque species is peculiar in its unusually short and 

 stout antennae and broad prosternal process, and quite unique in its 

 limited sexual clothing of the male tarsi. The metatarsal claws are 

 similar to, and quite as large as those of the pro- and mesotarsi. 



A. semivittatus Lee. Ann. Lye. Nat. Hist., New York, 1851, p. 204. 

 tetanus Shp. On Dytiscidae p. 505. 



A strongly shining black species of medium size, the elytra with a sublateral yel- 

 low vitta in nearly the posterior half, which is, however, sometimes interrupted 

 or quite obscure. Elytral reticulation fine and feeble, the areolae unequal and of 

 irregular form. All the essential characters are set forth in the table of species. 

 The very broad flattish prosternal process, itself widely margined for some dis- 

 tance behind the coxae, combined with the very small area of the basal tarsal 

 joint clothed with glandular hairs in the male afford a reliable means of identifi- 

 cation. The four anterior tarsi are only just visibly dilated in the male, the pads 

 of adhesive pubescence narrow and densely set with moderately small pallettes. 

 Length 7.5 to 8.8 mm. 



Semivittatus is widely dispersed in the great interior region of the 

 continent but seems not to attain the coast line of either the Atlantic 

 or the Pacific. Specimens have been seen from Ontario, Canada; 

 Ohio (Cincinnati) ; Illinois (Edgebrook) ; Nebraska (Malcom and 

 Kearney) ; Louisiana (Winnfield) ; Texas (Waco) ; Colorado 

 (Boulder); New Mexico (Las Vegas); Arizona (Tucson). 



Some examples, more especially those from Texas and the southwest 

 are a little less evenly oval than the typical form of the species, but the 

 difference is extremely illusory and seems not to be supported by any 

 structural characters. It is probable that the type of texanus Shp. is 

 one of these slight variants ; Sharp's description however fits just 

 as well in all respects the typical semivittatus, and I can see no reason 

 for giving te.ranus even varietal standing. The semivittatus of Sharp's 

 monograph is not the species so named by LeConte, but a quite distinct 

 species which is described below. 



A. johannis new species. 



This name is proposed for the Agabus semivittatus Lee. of Sharp's 

 monograph. Knowing the true semivittatus of LeConte, it was at 



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