204 FAMILY IV. DYTTSC'I U.K. 



389 (1231). CNKMIDOTI s 12-ri NCTATUS Say, Trans. Amer. Phil. Soc., II, 

 1823, 106; ibid. II, 518. 



Ovate, very convex. Dull yellow, each elytron with six 

 well defined black spots arranged as in the accompanying 

 ligure. Head finely, thorax rather coarsely and sparsely, 

 punctate. Elytra each with eight rows of large black punc- 

 tures and two rows of finer, paler ones on sides. Hind coxal 

 plates subangulate on hind margin. Length 3.5-4. (Fig. 

 103.) 



Northern half of State, common ; less so in the south- 

 ern counties. Often taken in numbers when seining. 

 M.nv 2f)-August 15. 



:;:>o < 1233). CNEMIDOTUS EDENTIH s Lee.. New sp. N. A. Col.. I. 1863, 21. 



Slightly more elongate and less convex than l.!-i>nnctatiis. Pale straw 

 yellow. Elytra more attenuate behind the middle and with spots larger, 

 often more or less confluent. Length 4 mm. 



Lake, Laporte, Marshall and Fountain counties; scarce. April 

 29-August 15. 



391 (1232). CNEMIDOTUS MUTICUS Lee., New Sp. N. Am. Col., I, 1863, 21. 

 Resembles 12-ininctatus in form and sculpture. Differs by having the 



hind femora wholly piceous or dark brown, the hind coxal plates broadly 

 rounded, and the elytra subtruucate at apex. The sutural black line is 

 narrowed on basal half and the median subsutural spot is confluent with it 

 to form a rather large irregular blotch. Length 3.5-4 mm. 



Throughout, the State; common. March 1-i-October 23. This 

 as well as the other species probably passes the winter as imago. 



392 (- -). CNEMIDOTUS PEDUNCULATUS Roberts MS. 



Very rl'.r.-o to the preceding. Differs mainly in the arrangement of the 

 elytral spots as mentioned in key. The sutural black line is wider, occupy- 

 ing the sutural interval on the basal half, and is not confluent with the 

 median spot. The elytra are feebly sinuate rather than subtruncate at 

 apex. Length 3-3.5 mm. 



Laporte. Marshall. Fountain. Marion and Lawrence counties; 

 scarce. May 11-October 23. 



Family IV. DYTISCID^E. 



THE PREDACEOrs DIVTXO P.EKTLES. 



Tn the (piiet. deep pools of streams, and in ponds or stagnant 

 water may often be seen oval, flattened beetles hanging bead down- 

 ward, with the tip of the abdomen at or slightly above the surface 

 of the water. These beetles belong to the family Dytiscidas, the 



