42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



achieved through characters of the ninth abdominal segment (figs. 

 7, a; 15, a, f; 16, a), impressions on the mesothorax and metathorax, 

 and through other differences discussed under the inflatus group 

 (p. 49). 



When mature, the larvae usually exceed 17 mm. in length. Dorsum 

 yellowish brown to bright yellow. Caudal notch large, U-shaped. 

 Urogomphi bifid, short and thick; prongs subequal in length with 

 sharp, horny tips ; tip of outer prong usually inclined backward, but 

 not continuing downward as in the cdzvardsi group. Ninth abdominal 

 segment with 3 or 4 prominent blunt tubercles or "teeth" on lateral 

 margins of dorsal plate, no setae or 2 or 4 setae on central dorsal area, 

 and distance between caudal notch and pleural area equal to one-sixth 

 to one-fifth total length of segment exclusive of urogomphi. Nasale 

 unidentate. Frontoclypeal area truncate posteriorly. Eyes well de- 

 veloped. Two pairs of lateroepicranial setae on each gena. Gula short 

 and wide. Mandibles robust, as in figure 2, e, f, h. Second segment 

 of antenna with one "sensory" appendix. Basal segment of labial 

 palpi without setae. Presternum of prothorax divided into 3 or 4 

 sclerites. Mesothorax and metathorax with short impressions (indis- 

 tinct in pruininus) on mediotergites, and with several spinelike setae 

 (up to 10) on each episternum. Mediotergites of second to eighth 

 abdominal segments with transverse branches of impressions usually 

 attaining less than one-half of distance from longitudinal branches to 

 middorsal suture, and with prominent setae arranged in pairs. Spir- 

 acles in anterior parts of segments. 



LUDIUS AERIPENNIS (Kirby) 



Figures 1-7; 9, /;, /; 10, d; 13, d; 14, e 



Elater aeripcnnis Kirby, in Richardson's Fauna Boreali-Americana, vol. 4, 



p. 150, 1837. 

 Corymbites tinctus LeConte, Proc. Acad. Nat. Sci. Philadelphia, p. 85, 1859. 

 Luditis elegans Schwarz, Wytsman, Genera Insectorum, pp. 46, 225, 322, 1907. 

 Ludius aeripennis (Kirby), Brown, Canadian Ent., vol. 67, pp. 127-129, 1935. 



This western species ranges from Alaska to Oregon and as far 

 east as Manitoba and the Dakotas, probably including western Minne- 

 sota. The subspecies destructor Brown (Brown, 1935b, p. 129), 

 referred to in the earlier economic literature as tinctus (LeConte) 

 or as aeripennis (Kirby), is widespread and abundant over the prairie 

 areas and adjoining parklands, but is replaced by the typical aeripennis 

 in the forested and mountainous regions to the north and west. Both 

 subspecies occur in the Peace River area of Alberta and British Co- 

 lumbia, destructor predominating in the open grassland sections. 



