NO. II LARVAE OF THE ELATERID BEETLES GLEN I7I 



Excluding Athous niger (Linnaeus) and its allies, all the Athous 

 larvae examined had the following characters in common: Pre- 

 sternum of prothorax undivided. Urogomphi bifid, usually with 

 prongs subequal or outer prongs longer than inner prongs. Dorsum 

 of ninth abdominal segment with median sulcus, without setae on 

 central area, and with prominent "teeth" (sometimes sharp) on lat- 

 eral aspects. Nasale tridentate at tip, denticles subequal. Subnasale 

 of many fine teeth. Eyes present. Two unpaired lateroepicranial setae 

 on each gena. Gula of moderate length, but narrow. One "sensory" 

 appendix on second segment of antenna. Mandible usually with well- 

 developed retinaculum but lacking other teeth or toothlike expansions. 

 Definite impressions on mediotergites of mesothorax and meta- 

 thorax. Abdominal mediotergites with long impressions, reaching 

 at least three-quarters of the distance to the mediodorsal suture ; 

 mediotergite sometimes with coarse deep pits or prominent trans- 

 verse rugae. 



KEY TO "species GROUPS" AND ISOLATED SPECIES OF ATHOUS 



1. Caudal notch small (fig. 34, c, J) 2 



Caudal notch large (figs. 34, h; 35, c) or moderately large (fig. 36, a) . . 3 



2. Abdominal mediotergites with numerous transverse rugae (fig. 34, e) ; 



North America the rufif rons group (p. 173) 



Abdominal mediotergites without transverse rugae ; Europe 



the vittatus group (p. 171 ) 



3. Urogomphi with outer prongs much longer than inner prongs (fig. 34, 



h) ; abdominal mediotergites without coarse punctures or prominent 



rugae; Europe A. mutilatus Rosenhauer (p. 174) 



Urogomphi with outer prongs not longer than inner prongs (figs. 35, 

 c, d ; 36, fl) ; abdominal mediotergites with coarse, prominent sculp- 

 ture (figs. 35, e; 36, c) 4 



4. Caudal notch only slightly narrowed posteriorly (fig. 35, c, j) ; mandible 



(fig- 35. 0) with medial expansion {ex) in region of penicillus; 



North America the cucuUatus group (p. 175) 



Caudal notch considerably narrowed posteriorly (fig. 36, a, d) ; mandible 

 without medial expansion at penicillus ; Europe and North America. . 

 the undulatus group (p. 177) 



THE ATHOUS VITTATUS GROUP 



Figure 34, a-c 



PROVISIONAL KEY TO SPECIES 



Inner prongs of urogomphi (fig. 34, a, c) with prominent posterior tubercle; 

 outer prongs with small denticle on inner aspect (sometimes absent 

 through erosion) ; fine sharp points on "teeth" {to) along lateral mar- 

 gins of dorsum of ninth abdominal segment 



A. haemorrhoidalis (Fabricius) 



