AQUATIC IXSBOTS IN NEW YORK STATE 293 



pp Apex Of the. abdomen not obliquely 

 truncate; antennae, with four seg- 

 ments Nitldulidae 



00 Ninth abdominal tergite not with short 

 cuticular spines 

 p Antennae consisting of four segnieuts 

 q Labrum distinctly present 



Nitldulidae 

 Oucujidae 



qg Labrum wanting E 1 at e r i d a e 



pp Antennae consisting of three segments 

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

 qq Labrum distinctly present 



Melandryidae 

 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 strongly chitinized and, if so, never 

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

 always produced into one or more prominent projections 

 ff 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 

 i Last abdominal segment produced into two strongly 

 chitinized, and bifurcating processes 

 / Abdomen strongly depressed. .Pyrochroidae 

 jj Abdomen cylindrical or subcylindrical, not strongly 

 depressed 

 A- Bifurcating process of the last abdominal segment 

 with lateral spines or tubercles 



Trogositidae 

 Jclc Bifurcating process of the last abdominal segment 

 not with lateral spines or tubercles 



Colydiidae 



Mycetophagidae 



Malachidae 



C 1 e r i d a e 



Melandryidae 



a Last abdominal segment produced into a single 



strongly chitinized process, which is usually slightly 



angularly emarginate at apex Mordellidae 



Jih Abdomen strongly and evenly chitinized throughout, 

 cylindrical or subcylindrical 



i Labrum wanting Elaterldae 



ii Labrum present and separated from the clypeus by a 

 distinct suture Tenebrionidae 



