38 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



Group III: Caudal notch small (fig. 11, /, h) ; prosternum un- 

 divided, consisting of one triangular sclerite (fig. 13, h) sometimes 

 deeply incised on posterolateral aspects. This combination of char- 

 acters is found in all species of Limonius, Elathous, and Lepturoides, 

 and in many species of Athoits. Proper characterization of the Ludius 

 that fall in this group can be made only on the basis of "species group" 

 characters as given in the key to genera, isolated species groups, and 

 isolated species of the tribe Lepturoidini (p. 34) or as discussed under 

 the species groups concerned: pyrrhos group, limoniiformis group, 

 and rcsplendens aerarius (Randall). 



Group IV: Caudal notch large (fig. 12, e) ; prosternum undivided, 

 consisting of one large triangular sclerite, much as represented in 

 figures 10, ^ and 13, b. These characters are found in Hypnoidus, 

 Hemicrepidius, Melanactes, and in some Athous. The only Ludius 

 falling in this group is divaricatus (LeConte) and it is readily sepa- 

 rated from other known Lepturoidini by the characteristic ninth 

 abdominal segment (fig. 24, c, d). 



Considering the genus in the broad sense in which it is currently 

 recognized, the mature larvae may be described as follows, characters 

 common to all species being marked with an asterisk : 



Length 14 to 30 mm. Shape varying from the robust pcctinicornis, 

 measuring 28 mm. by 4 mm., to the relatively slender cyVmdriformis, 

 measuring 30 mm. by 2.6 mm. Body usually widest across fourth 

 abdominal segment, but in some species widest across thorax and 

 first 2 abdominal segments ; some species very robust with relatively 

 small pleural membranes, others flattened with conspicuous large 

 pleural areas. Dorsum pale yellow to very dark brown; without 

 color pattern or distinctly patterned. *Urogomphi always bifid. Uro- 

 gomphal prongs varying tremendously as to shape and relative length. 

 Caudal notch large or small ; posterior aperture varying from wide to 

 almost closed. *Dorsum of ninth abdominal segment always with 

 "teeth" on lateral margins. Dorsal plate of ninth abdominal segment 

 varying from very convex to almost flat, the following characters 

 being present or absent: setae on central area, large pits, median 

 groove, and transverse impression. Frontoclypeal region reaching 

 to foramen magnum or failing to attain foramen ; terminating trun- 

 cate, broadly rounded, or bluntly pointed. Nasale of one tooth termi- 

 nating in one or three points. Subnasale highly variable. Eyes present 

 (usually) or absent; from 2 to 6 setae around each eye or eye region. 

 From 2 to 7 lateroepicranial setae in unpaired or paired arrangement. 

 Each dorsal head sulcus with 4 or 5 setae, sometimes additional minute 

 setae. Quia short and wide, or short and narrow, or elongate and 



