NO. II LARVAE OF THE ELATERID BEETLES GLEN 75 



Material used in study. — Two larvae were examined. Both had 

 been reared from eggs obtained from adults collected at Walla Walla, 

 Wash., by H. P. Lanchester and identified by M. C. Lane of Walla 

 Walla, but the adults were not retained. The specimens are the 

 property of the U. S, National Museum. One specimen (Truck Crop 

 No. 2762) was identified as L. pudicus Brown, but the other (Truck 

 Crop No. 2761) was identified as Ludius propola columbianus Brown. 

 On the basis of larval characters this specimen is believed to be of 

 the same species as larva No. 2762 and most likely to be L. pudicus 

 and not L. propola columbianus. The evidence in support of this 

 conclusion may be summarized as follows: (i) the two larvae are 

 morphologically indistinguishable, except in characters known to vary 

 between individuals ; (2) specimen No. 2761 is larger than any specimen 

 of the typical propola (which has been reared at the Saskatoon Labo- 

 ratory), but according to Brown (i936d), adults of propola colum- 

 bianus are not larger than those of propola propola, whereas adults 

 of pudicus are larger; (3) the larvae in question are definitely distinct 

 from the larva of propola propola, whereas the writer has not been 

 able to find diagnostic subspecific characters for other larval Elateridae 

 (e.g., in Ludius aeripennis, Ludius cupreus, and examples in other 

 genera) ; and (4) a misidentification of the adult could easily occur, 

 since Brown (i936d) writes in his description of L. pudicus (p. 183), 

 "Frequently the subbasal markings are not extended on the second 

 interval (of the elytra) and the specimens then resemble propola 

 columbianus in color." 



THE LUDIUS TRIUNDULATUS GROUP 



Figures 13, g; 14, d; 18 



KEY TO SPECIES 



Outer prongs of urogomphi standing erect, forming an angle of approxi- 

 mately 90° with the undivided base of each urogomphus (fig. 18, e) ; 

 Montana, Washington, British Columbia, .nebraskensis (Bland) (?) (p. 81) 



Outer prongs of urogomphi projecting caudodorsad, forming an angle of 

 approximately 130° with the undivided base of each urogomphus (fig. 

 18, /) ; coast to coast in Canada triundulatus (Randall) (p. 76) 



Knowledge of this group is based upon the larva of triundulatus 

 (Randall) and upon a larva which is probably nebraskensis (Bland). 



The closest relatives are found in the propola group from which 

 distinction is secured through characters of the urogomphi (fig. 18, 



