192 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



of which several to many were apparent within each of the larger 

 genera as recognized in the current taxonomic literature. In effect, 

 each genotype was representative of but one "species group." 



Some of the larger genera are too complex to be adequately char- 

 acterized. This is particularly true of Ludiiis and Athous and to a 

 lesser degree of Limonius. On the basis of the material studied, 

 the following genera appear to be sufficiently homogeneous to per- 

 mit of characterization: Crepidomenns, Cryptohypnus, Hypnoidus, 

 Eanus, Elathous, Lepturoides, Hemicrepidius, and Melanactes. How- 

 ever, larvae of only one to five species were available for each of 

 these genera and insufficient representation may account for this 

 apparent homogeneity. 



In general, the taxonomic value of any character or set of char- 

 acters changes from one "species group" to another. However, 

 throughout the tribe studied certain characters have maintained a 

 high ordinal value. Simple urogomphi and bifid urogomphi have not 

 been found within the same genus ; and the type of caudal notch, 

 the general type of prosternum, and the general type of nasale have 

 varied comparatively little between species of the same "species 

 group." Accordingly, these are regarded as primary group char- 

 acters, their relative importance being as in the order stated. On the 

 basis of these characters the general relationships between the "spe- 

 cies groups" of Ludius and the other lepturoidine genera are charted 

 on page 191. 



THE GENUS LUDIUS 



The "species groups" of Ludius that have been erected on the 

 basis of larval characters agree closely with those independently 

 estabUshed by Brown (1935, 1936, 1939), who studied the adults 

 of the American species. Where adequate larval material was avail- 

 able, Brown's groups were invariably substantiated, but where the 

 larvae of only a very few species were known or where the material 

 was not suitable for a complete examination, the larval study sug- 

 gested fewer groups than Brown had erected. The writer agrees 

 completely with the following statement (Brown, 1935a, p. i) : "The 

 genus Ludius, as now recognized in the American literature, is not a 

 true genus in any natural sense, but is, rather, a heterogeneous group 

 of species the natural affinities of which are not known." Similar 

 conclusions have been reported by Blatchley (1910, p. jG^^) and by 

 Van Dyke (1932, pp. 389-390), who studied the adults, and by Hen- 

 riksen (1911, p. 258), who described the larvae of seven species. 



