It is one of the most iin])ortant groups of aquatic insects, both 

 on account of the food its members furnish to fishes, and also 

 because of the serious injuries Avhich some bugs do to fish eggs 

 and fry. The genera Eanatra and Belostoma are especially to be 

 remembered as containing some of the worst insect enemies to 

 fishes of which we know. Most of tliem begin a predatory life as 

 soon as hatched from the egg, and continue it without ccsssation 

 throughout their existence. The common food is larvje of other 

 insects, mollusks, and the like. The eggs are generally deposited 

 on aquatic plants, sometimes enclosed in gelatinous matter, but in 

 many cases quite naked. Corisa sometimes places its eggs on the 

 shells of crayfishes. Eight families of the order have common 

 representatives in the waters of the State. Of these, five are rep- 

 resented in the collection made at Quincy. 



Family Hydrobatid^. (Crazy Bugs.) 

 Limnotrechus marginatus, Say.. 



(Gem's marginatus, Say, Heteropterous Hemiptera, lt31, 807.) 



A small slender-bodied insect about .40 inch long, with long 

 slender legs by means of which it pushes itself along on the sur- 

 face of the water. The whole under surface of the body is covered 

 with a silvery coating which repels the water and so aids the 

 insect in its singular method of locomotion. The eggs are at- 

 tached to aquatic plants, and the young pup;Te resemble the 

 grown insect except for the wings and increased size. In winter the 

 adults are found under rubbish in the shallow water at the edges 

 of streams. The species was common in a number of the sloughs 

 and was noted especially in Harkness Slough, Willow Slough, and 

 Tiong Lake. 



Stepliania picia, H. Sch. 



(Uhler, Stand. Nat. Hist., ii, 270.) 



A small brightly colored insect taken only in Wood Slough and 

 Long Lake. 



Family Veliid^. 



Mesovelia hisignaia, Uhler. 



(Uhler, Stand. Nat. Hist., ii, 274.) 



A small greenish yellow insect about .12 inch long, which is fre- 

 quently found on the surface of water. Frequent at edges of 

 Willow Slough Aug. 15. 



Family Belostomatid^. 



Benacns griseiis, Say. 



This is one of the large, flat, predaceous bugs that sometimes 

 become destructive to young fishes. It is reported by Mr. C. A. 

 Hart, of this Laboratory, as common at the electric lights in 



