NO. II LARVAE OF THE ELATERID BEETLES GLEN 95 



3. Eastern United States; the most posterior of the blunt "teeth" (to, 

 fig. 21, /) on lateral margins of dorsal plate of ninth abdominal 



segment more than one-half as long as broad 



rotundicollis (Say) ("eastern species") (p. 96) 



Western United States; the most posterior of blunt "teeth" (to, fig. 21, h) 

 on lateral margins of dorsal plate only one-half (or less) as long 

 as broad rotundicollis (Say) ("western species") (p. 97) 



On the basis of laival characters, three species have been included 

 in this group, namely, rotundicollis (Say), sulcicollis (Say), and the 

 European cinctus (Paykull). The larvae (figs. 21, h; 22, a) of these 

 species are noticeably well supplied with setae and differ from all 

 other Ludiiis larvae examined in having the proxistipes and dististipes 

 clearly separated (fig. 22, h). All are wood inhabiting and appear to 

 be chiefly predaceous ; they are commonly found just under the bark 

 of decaying stumps and logs or of living trees, frequently in the 

 galleries of wood-boring beetles. 



The species are quite distinct and easily recognized and it might 

 be that two, or even three, closely related groups are represented 

 by the species that have been brought together here. However, it 

 is believed preferable to retain them in one group until larval ma- 

 terial of other related species is available for study. On the basis 

 of adult characters, Van Dyke (1932, p. 428) groups the following 

 North American species: rotundicollis (Say), sulcicollis (Say), 

 rupestris (Germar), and nunenmacheri Van Dyke. Larvae of the 

 last two species were not available for examination. 



The larva of the European Ludius bipustulatus (Linnaeus) re- 

 sembles the rotundicollis group in color, general setal characters, 

 nasale, and in several other respects; but it differs in urogomphal 

 prongs, sculpture of abdominal segments, type of sternum in ab- 

 dominal segments, pleurite of ninth abdominal segment, mandibles, 

 and maxillary stipites. 



Larvae of the rotundicollis group vary in color from bright brown 

 to very dark brown, sometimes with the dorsum distinctly patterned 

 (fig. 22, a), venter always pale. Caudal notch large, U-shaped. 

 Urogomphi bifid ; prongs subequal or outer prongs larger than inner 

 prongs ; tip of inner prong sharp, upturned ; tip of outer prong 

 bluntly rounded. Ninth abdominal segment (figs. 21, g; 22 c) with 

 moderately large pits on dorsum ; usually without setae (rarely with 

 2 small setae) on central dorsal area; 2 to 4 blunt "teeth" on lateral 

 margins of dorsum; distance from pleural area to caudal notch ap- 

 proximates one-tenth to one-eighth total length of segment ; and with 

 large pleurite (pi, fig. 21, h) anteriorly on each side. Nasale uni- 



