NO. II LARVAE OF THE ELATERID BEETLES — GLEN I43 



p. 391) sjaclandicus also inhabits the northeastern part of North 

 America, but no larvae have been obtained from this region. 



Larvae have been collected from rotten birch, sphagnum, and cow 

 dung, but the typical habitat is the moist soil of low-lying land such 

 as peat moors, alder swamps, grassy meadows, and damp, moss- 

 covered parts of forests. Injury to domestic plants frequently results 

 when such areas are brought under cultivation. Durnovo (1935) 

 reports this species as a pest of vegetables on peaty soil recently 

 cleared of alder. He further states that the larvae are much less 

 numerous in clayey soils and practically absent from sandy areas. 

 Pupation occurs in late July or early August. 



The larva has been described from Denmark by Schiodte (1870, 

 p. 521) and Henriksen (1911, pp. 261-262), and from Germany by 

 Beling (1883, pp. 272-273, "tessellatus L."). It is readily recognized 

 by having the spiracles situated in the posterior half of the eighth 

 abdominal segment {sp, fig. 27, d), but not enlarged as in the pyrrhos 

 group. The larva is further characterized by its bright yellow color ; 

 tridentate nasale («, fig. 27, a) ; presternum of prothorax divided into 

 3 parts; ninth abdominal segment (fig. 27, c, d) with small caudal 

 notch {en), urogomphi {nr) bifid with inner prongs {ipr) slightly 

 longer and much more robust than outer prongs (opr), 2 setae on 

 central dorsal area, and 3 prominent blunt teeth (to) on lateral mar- 

 gins of dorsum. 



Description of "mature" larva. — Length 22 mm. ; greatest breadth 

 3.0 mm. on fourth and fifth abdominal segments. Henriksen (1911, 

 p. 262) and Beling (1883, p. 272) record specimens measuring 26 mm. 

 in length. Body robust ; with moderately large membranes on lateral 

 aspect ; all segments broader than long ; head and ninth abdominal 

 segment about three-fourths greatest body width. Dorsum bright 

 yellow (near "hazel" or slightly darker than "ochraceous buff," Ridg- 

 way, 1912) ; mandibles, nasale, talus, and prongs of urogomphi darker ; 

 venter slightly paler. Dorsum shiny ; slightly rugose ; with a few 

 small and very shallow inconspicuous pits. 



Head subquadrangular with arcuate sides, about as thick at base 

 as long ; flattened above and below. 



Frontoclypeal region with posterior part extending backward almost 

 to foramen magnum, truncate posteriorly. Two prominent anterior 

 nasosulcal setae on each side of base of nasale. Nasale («, fig. 27, a) 

 with tip tridentate when uneroded ; median denticle largest, lateral 

 denticles projecting anterolaterad. Subnasale (sn) consisting of 

 strongly sclerotized transverse ridge with large, forward-projecting 



