NO. II LARVAE OF THE ELATERID BEETLES GLEN III 



THE LUDIUS NITIDULUS GROUP 



Figures 13, a; 14, t; 23 



KEY TO SPECIES 



1. From North America ; outer prongs of urogomphi about twice as large 



as inner prongs (fig. 2Z, e, g) 2 



From Europe ; outer prongs of urogomphi not larger than inner prongs 

 or only slightly larger (fig. 23, /) nigricornis (Panzer) (?) (p. Il8) 



2. Nasale and adjoining area of frons deeply sunken; nasale (fig. 23, c) 



narrow, tip divided into 3 narrow, forward-projecting denticles 



rufopleuralis Fall ( ?) (p. 117) 



Nasale and adjoining area of frons only slightly depressed; nasale (n, 

 fig. 23, 0) broad, tip tridentate, median denticle largest, lateral den- 

 ticles projecting anterolaterad nitidulus (LeConte) (p. 112) 



Knowledge of this group is based upon larvae of nitidulus (Le- 

 Conte) and upon larvae that are believed to be rufopleuralis Fall or 

 aratus (LeConte) and other unidentified larvae that are regarded as 

 the European nigricornis (Panzer) or a closely related species. 



From the fragmentary data that are available, the principal larval 

 habitat appears to be the litter of the forest floor. The larvae are be- 

 lieved to be chiefly predaceous. 



These larvae differ from other known Ludiiis larvae in possessing 

 2 conspicuous dorsal posteroepicranial setae (ped, fig. 23, a) on each 

 side of the frontal sutures near the posterior limit of frons. In this 

 they resemble the larvae of Cryptohypnus, Melanactes, and the Aus- 

 tralian genus Crcpidomenus. However, the nitididus group is readily 

 distinguished from these genera by the following combination of char- 

 acters : Eyes present ; outer urogomphal prongs {opr, fig. 23, ^) curv- 

 ing forward ; blunt "teeth" on the lateral margins of the dorsal plate 

 of the ninth abdominal segment {to, fig. 23, g) ; abdominal medio- 

 tergites (fig. 23, h) without conspicuous transverse rugae and with 

 impressions reaching to or almost to the middorsal suture on second 

 to eighth segments; and setal pattern on abdominal mediotergites as 

 figured. 



The larvae are yellowish brown. Moderately large caudal notch, 

 U-shaped. Urogomphi bifid; prongs subequal or outer prongs larger 

 than inner prongs ; tips of prongs sharp, tips of outer prongs inclined 

 forward. Ninth abdominal segment (fig. 23, g) with 3 prominent 

 blunt "teeth" on lateral margins of dorsum and typically with 4 setae 

 on the central dorsal area. Nasale {n, fig. 23, a; fig. 23, c, d) with 

 tip tridentate, denticles of varying character. Frontoclypeal area (fig. 

 23, a) broadly rounded posteriorly. Second joint of antenna bear- 

 ing I sensory process. Gula of moderate width and length. Mandi- 



