AQUATIC INSECTS IN NEW YORK STATE 293 



pp Apex of the abdomen not obliquely 

 truncate; antennae with four seg- 

 ments N i t i d u 1 i d a e 



00 Ninth abdominal tergite not with short 

 euticular spines 

 p Antennae consisting of four segnjonts 

 q Labrum distinctly present 



N i t i d u 1 1 d a e 

 C u c u J i d a e 



qq Labrum wanting E 1 a t 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 



I\I e 1 a n d r y i d a e 

 ee Apex of the abdomen strongly chitinized and usually produced 

 into one or more prominent projections 

 / Entire abdomen strongly chitinized and cylindrical, the apex 

 squarely truncate and not produced into projections 



Rhiiiiceridae 

 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 

 g Antennae consisting of four segments 



/( 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 

 Ik Bifurcating process of the last abdominal segment 

 not with lateral spines or tubercles 



Colydiidae 



INIycetophagidae 



Malachidae 



C 1 e r i d a e 



]M eland ryidae 



n Last abdominal segment produced into a single 



strongly chitinized process, which is usually slightly 



angularly emarginate at apex M o r d e 1 1 i d a e 



/(/( Abdomen strongly and evenly chitinized throughout, 

 cylindrical or subcylindrical 



i Labrum wanting Elate ridae 



a Labrum present and separated from the clypeus by a 

 distinct suture Tenebrionidae 



