34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



KEY TO GENERA, ISOLATED "SPECIES GROUPS," AND ISOLATED SPECIES 

 OF THE TRIBE LEPTUROIDINI 



1. Urogomphi undivided (ur, fig. lo, a, b) 2 



Urogomphi divided: prongs subequal (figs. lo, /; ii, /; 12, a, f), or 



unequal (figs. 11, a; 12, b, c, e) 3 



2. Urogomphi blunt (fig. 10. a) ; abdominal pleurites absent (fig. 10, 



c) Eanus (p. 187) 



Urogomphi sharp (fig. 10, 6) ; abdominal pleurites large. Hypnoidus (p. 186) 



3. Head bearing dorsal posteroepicranial setae {pcd, fig. 10, y) ; thoracic 



segments and first 8 abdominal segments bearing medial antero- 



tergal setae {atm, fig. 10, f/) 4 



Without dorsal posteroepicranial setae ; usually without medial antero- 



tergal setae 7 



4. Ninth abdominal segment (fig. 10, /) with sharp "teeth" {to) on 



sides of dorsum and 2 setae on central dorsal area ; Aus- 

 tralia Crepidomenus queenslandicus Blair (p. 181) 



Ninth abdominal segment with well-rounded "teeth" on sides of dorsum 

 and 4 setae on central dorsal area 5 



5. Abdominal mediotergites (as in fig. 12, d) with conspicuous trans- 



verse rugae (crescent-shaped shallow pits, which are sometimes 

 confluent); eyes absent; larvae attaining more than 30 mm. in 



length Melanactes densus LeConte (p. 189) 



Abdominal mediotergites without such sculpturing ; eyes present 6 



6. Abdominal mediotergites with transverse branch of impressions extend- 



ing to or practically to the mediodorsal suture on second to eighth 



segments Ludius, the nitidulus group (p. in) 



Abdominal mediotergites with transverse branch of impressions extend- 

 ing approximately one-half the distance from the longitudinal 

 branch to the mediodorsal suture Cryptohypnus (p. 183) 



7. Spiracles in eighth abdominal segment {sp, fig. 11, c) twice as long as 



spiracles in seventh abdominal segment 



Ludius, the pyrrhos group (p. 147) 



Spiracles subequal in size in seventh and eighth abdominal segments. ... 8 



8. Presternum of prothorax divided into 2 or more sclerites {prst, fig. 



10, d) Ludius, pars majora (p. 35) 



Presternum of prothorax undivided, of i large triangular sclerite {prst, 

 fig. 10, e) 9 



9. Caudal notch small (figs. 11, a, j ; 12, b) 10 



Caudal notch large (fig. 12, a, c, f) 16 



10. Outer prongs of urogomphi reduced to mere tubercles {opr, fig. 11, 



a, d) Limonius, pars (p. 157) 



Outer prongs of urogomphi definitely pronglike {opr, figs. 11, b, g; 

 12, b) II 



11. Outer prongs of urogomphi not longer than inner prongs (fig. 11, j-h) . 12 

 Outer prongs of urogomphi much longer than inner prongs (fig. 12, 



b) 



Ninth abdominal segment with a distinct (sometimes short) mediodorsal 



groove (mg, fig. 11, /) ; eyes present; North America 13 



Ninth abdominal segment without a mediodorsal groove (fig. 11, g, h) ; 



eyes absent in North American species 14 



