Animals of the Mississippi Bottoms near Quincy. 169 



supposed to be carnivorous. The larv;e are greatly flattened 

 and live under rocks, sometimes in rapid currents. 



Stenelnus viitipennis, Zimm. 



(Trans. Am. Ent. Soc, ii, 259, 1869; Horn, ibid, iii, 40, 

 1870-71.) 



Taken in Willow and Wood Sloughs. 



Macroni/chus glabratus, Say. 



(Say, Jour. Acad. Nat. Sci. Phil., N. Ser., v, 187, 1827; 

 Compl. Writ., ii, 292.) 



Wood Slough, Aug. 4. Not common. 

 Family Heterocerid^]. 



Heterocerus undatus, Mels. 



This is a small brown pubescent beetle about .20 inch long, 

 with a few irregular yellow marks on the wing covers. 



It occurred in very great numbers in the earth at the 

 edges of the more isolated sloughs, in burrows resembling 

 miniature mole hills. When the seines brought the water over 

 the burrows the beetles at once appeared and took flight. The 

 larvae also were present in abundance, and were found at times 

 exposed on the surface of the water. 



My attention was especially drawn to the curious little 

 mud cases which the larvae construct when ready to pupate, 

 and of which I have seen no published description. The cases 

 are always made in the moist mud at the immediate edge of the 

 water and are carefully detached from the adjacent soil, so that 

 each stands in a little hollow. From one side arises a closed 

 chimney often equal in height to the basal portion of the case. 

 The beetles were emerging from the cases on the 11th of Au- 

 gust, always making their way out by creeping up the chimney 

 and breaking through its extremity. The beetles were seen 

 along most of the sloughs and lakes. The mud cases were 

 noted as especially abundant along Long and Broad Lakes and 

 Harkness Slough. At the edge of the first-named lake eighteen 

 of the cases were counted on an area about one foot square. 

 The food of both adults and larvae consists of brown granular 



