AQUATIC INSECTS IX NEW YORK STATE 293 



pp Apex of the abdomen not obliquely 

 truncate; antennae witU four seg- 

 ments Nitidulidae 



00 Ninth abdominal tergite not with short 

 cuticular spines 

 p Antennae consisting of four segments 

 q Labrum distinctly present 



Nitidulidae 

 Cucujidae 



qq Labrum Avanting Elate ridae 



pp Antennae consisting of three segments 

 q Labrum -wanting. . . . L a m p y r i d a e 

 qq Labrum distinctly present 



INIelandryidae 

 ee Apex of the abdomen strongly chitinized and usually produced 

 into one or more prominent projections 

 f Entire abdomen strongly chitinized and cylindrical, the apex 

 squarely truncate and not produced into projections 



Rhipiceridae 

 ff Entire abdomen not stK)ngly chitinized and, if so, never 

 truncate at the apex; flattened or cylindrical, and the apex 

 always produced into one or more prominent projections 

 g Antennae consisting of four segments 



h Abdomen strongly chitinized only around the bases of 

 the chitinous projections of the apex of the tergum; 

 usually somewhat flattened 

 t Last abdominal segment produced into two strongly 

 chitinized and bifurcating processes 

 j Abdomen strongly depressed ..Pyrochroidae 

 ;7 Abdomen cylindrical or subcylindrical, not strongly 

 depressed 

 k Bifurcating process of the last abdominal segment 

 with lateral spines or tubercles 



Trogositidae 

 Ik Bifurcating process of the last abdominal segment 

 not with lateral spines or tubercles 



Colydiidae 



Mycetophagidae 



M a 1 a c h i d a e 



C 1 er idae 



Melandryidae 



ii Last abdominal segment produced into a single 



strongly chitinized process, which is usually slightly 



angularly emarginate at apex Mordellidae 



hh Abdomen strongly and evenly chitinized throughout, 

 cylindrical or subcylindrical 



i Labrum wanting Elateridae 



n Labrum present and separated from the clypeus by a 

 distinct suture Tenebrionidae 



