NO. II LARVAE OF THE ELATERID BEETLES GLEN 12$ 



Knowledge of this group is based upon an examination of larvae of 

 the American species kendalli (Kirby), and the European cupreus 

 (Fabricius) and pectiuicornis (Linnaeus) and upon Beling's descrip- 

 tion of virens (Schrank). 



These larvae are entirely soil inhabiting. Pupation occurs in an 

 earthen cell in late July or early August. Transformation to the 

 adult state is completed in from 2 to 4 weeks, but the beetle over- 

 winters in its pupal chamber. The larvae of at least two of these 

 species are known to be serious pests of crops for 2 or 3 years after 

 their natural habitat has been brought under cultivation. 



The group is very homogeneous and readily distinguished by the 

 combination of extremely small abdominal pleurites {pi, fig. 25, e) 

 and the presence of spinelike setae on the episterna of the mesothorax 

 and metathorax. Among the known Ludius larvae there is no group 

 that is closely related to cupreus. Superficial resemblance is found in 

 the larva of appressus (Randall), but separation is accomplished 

 readily through the urogomphi (fig. 25, g, h), subnasale (fig. 25, a), 

 impressions on abdominal segments (fig. 25, d), and setation of the 

 episterna of mesothorax and metathorax. 



When mature, the larvae usually exceed 20 mm. in length. Dorsum 

 yellowish brown to very dark brown. Caudal notch small, subovate, 

 nearly closed posteriorly. Urogomphi bifid ; prongs subequal in length 

 or outer prongs longer (virens) ; inner prong broad, outer prong 

 corniform with sharp tip usually inclined forward. Ninth abdominal 

 segment (fig. 25, h) without median dorsal groove; with 2 setae 

 (rarely 4) on central dorsal area; 3 "teeth" (to) on lateral margins 

 of dorsal plate ; and distance from pleurite to anterior margin of 

 caudal notch approximately one-fifth to one-fourth total length of 

 segment, exclusive of urogomphi. Nasale unidentate. Subnasale 

 (fig. 25, a) with transverse row of from 14 to 17 denticles. Fronto- 

 clypeal area truncate posteriorly. Eyes present. Gula short, narrow. 

 Mandible robust, much as in aeripennis group. Second segment of 

 antenna with i "sensory", appendix. Basal segment of labial palpus 

 without setae. Presternum of prothorax divided into 4 sclerites. With 

 few (up to 4) spinelike setae on episterna of mesothorax and meta- 

 thorax. Mediotergites of abdominal segments (fig. 25, d) with trans- 

 verse branches of impressions reaching from one-half to two-thirds 

 distance from longitudinal branches to middorsal suture and with 

 prominent setae unpaired or semipaired. Sternum undivided in first 

 8 abdominal segments. Spiracles in anterior half of each segment. 



