AQUATIC INSECTS IN NEW YORK STATH 293 
pp Apex of the abdomen not obliquely 
truneate; antennae with four seg- 
PACU SMe arash sees clack « Nitidulidae 
oo Ninth abdominal tergite not with short 
cuticular spines 
p Antennae consisting of four segmerts 
q Labrum distinctly present 
Nitidutidae 
Cucujpidave 
qq Labrum wanting......Hlateridae 
pp Antennae consisting of three segments 
q Labrum wanting....Lampyridae 
eq 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 
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 
i Last abdominal segment produced into two strongly 
chitinized and bifurcating processes 
j Abdomen strongly depressed..Pyrochroidae 
jj Abdomen cylindrical or subcylindrical, not strongly 
depressed 
k Bifurcating process of the last abdominal segment 
with lateral spines or tubercles 
Trogositidae 
kk Bifureating process of the last abdominal segment 
not with lateral spines or tubercles 
Colydiidae 
Mycetophagidae 
Malachidae 
Cleridae 
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, 
eylindrical or subcylindrical 
ACAI NY TUCINE, | sete ns ereve ese dw steers Hlateridae 
ii Labrum present and separated from the clypeus by a 
CHSMUICT S RINCILLO. sis Va siete sv tare ee wo Tenebrionidae 
