NO. II LARVAE OF THE ELATERID BEETLES GLEN 37 



the group increases. Only one record has been found in the Hterature 

 to date of any species of Ludius (L. ampHcollis) normally completing 

 its life cycle within i year. 



Concerning the structural features of the genus Ludius, Henriksen 

 (1911, p. 258) states (translation) : "A genus which it is very diffi- 

 cult to define, as the known larvae show such variation in charac- 

 ters." The writer agrees fully with this statement. So much hetero- 

 geneity exists in the larvae assembled that no single character or 

 combination of characters has been found which adequately defines 

 the assemblage as a natural group. 



However, all Ludius larvae examined have the urogomphi bifid 

 and are thus distinguished from Hypnoidiis and Eaniis. Separation 

 from Cryptohypmis and Crepidoinenus is obtained for all known 

 Ludius, except the nitidulus group, through the absence of dorsal 

 posteroepicranial setae {ped, fig. lo, g). With the exception of seven 

 species (divaricatus, resplcndcns, sjaclandicus, pyrrhos, protractus, 

 limoniifonnis, and cylindriforinis), all the Ludius examined have 

 the prosternum divided and are thus separable from the larvae of 

 Limoniiis, Elathous, Lepturoidcs, Athous, Hemicrepidius, and Mela- 

 nactes. Of these seven species, divaricatus is quite isolated from other 

 known Lepturoidini, and the other six probably are annectant species, 

 as mentioned by Van Dyke (1932, p. 389), connecting Ludius with 

 Limonius and with the Athous complex. 



Because of these findings the writer feels justified in stressing 

 the taxonomic value of characters of the prosternum. By combining 

 the characters of the caudal notch and the prosternum, four major 

 groups of Ludius have been established. These form a good working 

 basis for the identification of the larvae of this genus. 



Group I: Caudal notch small (fig. 14, h, g) ; prosternum divided 

 into two or more sclerites (figs. 10, d; 13, a). This combination of 

 characters is unique in the known Lepturoidini with the exception of 

 Eanus, which is readily distinguished by the undivided urogomphi. 

 This group includes the cuprcus group, appressus (Randall), and 

 sjaelandicus ( M iiller ) . 



Group II: Caudal notch large (figs. 13, /i; 14, c, i, j) ; prosternum 

 divided into two or more sclerites (figs. 10, d; 13, a). Cryptohypmis 

 and Crepidoinenus larvae also possess these characters, but are dis- 

 tinguished by a combination of sculptural and setal patterns. This 

 group includes two-thirds of the species of Ludius known in the 

 larval stage : aeripennis group, inflatus group, edwardsi group, semi- 

 vittatus (Say), propola group, triundulatus group, fallax group, 

 rotundicollis group, bipustulatus (Linnaeus), and nitidulus group. 



