99 



A common and widely distributed species. The long intestine 

 is filled with matter like that found in HijdropJilhis nimhahis, — 

 probably largely decaying vegetable matter. Mixed with the 

 granular matter are many diatoms and bits of filamentous algse. 



Localities: Harkness Slough, Willow Slough, Cedar Creek, 

 Long Lake, Wood Slough. 



Berosus siriaiiis. Say. 



{Hydrophilus siriaiiis, Say, Jour. Acad. Nat. Sci. Phil., N. Ser., 

 V, 188, 1825; Compl. Writ., ii, 292.) 



Food like that of the preceding species, the only recognizable 

 objects in the alimentary canals being in this cases diatoms. 



The species is abundant in Cedar Creek, and was founci also in 

 Ballard Slough. 



Hydrophilidce, larva (1). 



A small larva with depressed and rather stout body, with a 

 median brown band on the head and a pair of obscure dusky 

 longitudinal stripes on the abdomen above. Pale below. Sides of 

 thorax and abdomen tuberculate. The mandibles are unlike any 

 we have seen. They are rather long, sickle-shaped, and bear at 

 about the middle of their inner edge a strong tooth with bicuspid 

 apex, minute denticles on its anterior edge, and one or two small 

 teeth at its base. The largest example taken is a trifle more 

 than a half inch long. 



Locality, Cedar Creek. 



Hydrophilidce, larva (2). 



A small larva about .25 inch long, common in Cedar Creek, is 

 evidently the young of one of the above species of Berosus. The 

 body is widest at the middle and tapers pretty uniformly to the 

 extremities. Head small; ocelli superior; clypeus denticulate. 

 Basal segment of maxillae unusually long and strong. Segments 

 of body coarsely wrinkled, the seven anterior di^-isions of the 

 abdomen each with a pair of long naked respiratory 'filaments. 

 Terminal segment nipple-shaped; no caudal appendages. Young 

 examples are transparent in life, but grow more opaque when 

 older. 



Family Staphylinid^. (Eove Beetles.) 



Small species of this family of beetles were always common in 

 the mud and sand at the edges of sloughs, and many were noticed 

 floating and struggling on the surface in the latter part of Au- 

 gust, after the water had risen suddenly. 



Family Parnid.e. 



These are small beetles with tarsi of five segments, of which the 

 last one is as long as all the others together and carries two very long 

 simple claws. The body is frequently elongated and subcylindrical, 



