274 On Aquatic Carnivorous Colcoplera or Dytiscida. 



The disposition of the marks on the elytra is quite similar to that existing in 

 Canthydrus grammicus (No. 50), but the black marks are broader ; the difference 

 in the punctuation of the elytra renders the two very distinct. I have seen only 

 a single individual, which is probably a male, it has the apical ventral segment, 

 flattened or depressed except at the base. 



South California, (Cape St. Lucas). 499. 



49. Canthydrus centralis, n. sp. — Ovalis, sat convexus, pernitidus, testaceus 

 prothorace disco infuscato ; elytris uigris, vittis tribus testaceis, subseriatim 

 punctatis. Long. 3, lat. ll m.m. 



In this species the black colour on the wing-cases predominates the yellow, so 

 that this latter forms three rather narrow longitudinal stripes ; these commence at 

 the base, and are there broadest, the internal one becoming gradually more 

 indistinct behind, does not reach the extremity, the second is shorter and extends 

 but little beyond the middle, the third extends to the apex, and in front sends off 

 a branch to the shoulder, which is thus largely yellow ; besides these stripes the 

 lateral margin in the middle is yellow. Although the surface is very polished, the 

 subseriate punctuation of the elyti'a is very distinct, and on careful examination 

 traces may be discovered of an irregular very obsolete punctuation. The sexes 

 show little difference except in the tarsi, each having the greater part of the last 

 ventral segment a little hollowed. 



Guatemala, (S. Geronimo, 1879, Champion). 11G8. 



50. Canthydrus grammicus, n. sp. — Ovalis, latiusculus, sat convexus et elongatus, 

 pernitidus, rufo-testaceus ; elytris sutura vittisque tribus (externa interrupta) nigris ; 

 elytris j^unctis paucis subseriatis. Long. 3|, lat. 2 m.m. 



The sutural vitta extends to the apex, the one next to it nearly to the apex, 

 while the middle one is considerably abbreviate, the outer one does not reach the 

 shoulder, but there is a short humeral stripe which overlajis it. I have seen only 

 four individuals, which are all females, and have the last ventral segment impressed 

 on each side so as to make the middle part ajjpear prominent. 



South America; Amazons. 498. 



51. Canthydrus concolor, n. sp. — Oblongo-ovalis, posterius acuminatus, convexus, 

 nitidus, fulvus, elytris sparsim inconspicue punctatis. Long. 2|, lat. 15 m.m. 



This species resembles the larger individuals of Hydrocanthus flavus (No. 70) 

 exactly, but appears to me to have the posterior tarsi, shorter and thicker. 



Madagascar. 491. 



