NO. II LARVAE OF THE ELATERID BEETLES GLEN I47 



num of 2 sclerites, separated anteriorly by median longitudinal suture, 

 and posteriorly by tenth abdominal segment ; each sclerite with 2 or 3 

 setae in row around tenth abdominal segment. 



Urogomphi (wr, fig. 27, c, d) separate, robust, bifid; inner prong 

 slightly longer and much more robust than outer prong. Inner prongs 

 {ipr) short, stout, with hard, dark anteromedian margins ; directed 

 inwardly; tips bluntly pointed, frequently meeting or overlapping; 

 each with 2 stout setae, i issuing from base of small tubercle on 

 caudolateral margin and i from midventral surface. Outer prongs 

 {opr) shorter and more slender than inner prongs, projecting upward, 

 sometimes slightly outward and backward ; each terminating in horny 

 tip, sometimes with short, sharp point inclined inward ; 2 large setae, 

 I on anteromedial surface of distal half of prong, the other at base of 

 prong on lateroventral aspect. Undivided part of urogomphus short 

 and very broad, with i stout seta ventrally just anterad to bases of 

 prongs. 



Caudal notch {en) small, subovate or shield-shaped, slightly longer 

 than wide ; very narrow posteriorly, often entirely closed by converg- 

 ing inner prongs. 



Tenth abdominal segment {10) surrounded by 10 prominent setae; 

 anal aperture linear and median. 



Material used in study. — Fourteen larvae were examined. These 

 were collected from Denmark (6), Finland (5), and Germany (3), 

 So far as is known, none of these specimens were collected at the 

 same time and place as specimens that subsequently were reared, but 

 the larva of this species has been known to European workers for 

 many years and it is believed that the material is reliably named. The 

 material examined is deposited in the Canadian national collection, the 

 U. S. National Museum, and van Emden's collection. 



THE LUDIUS PYRRHOS GROUP 



Figures ii, e; 28 



KEY TO SPECIES 



From eastern North America pyrrhos (Herbst) (p. 148) 



From western North America protractus (LeConte) (p. 149) 



Knowledge of this group is limited to rather inadequate larval 

 material of pyrrhos (Herbst) and protractus (LeConte). The group 

 dilifers from all other known Ludius larvae in the character of the 

 spiracles of the eighth abdominal segment (figs, ii, e; 28, a), which 



