66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



of the first abdominal segment (pi, fig. 16, b) are virtually as long 

 as the sternum, in edwardsi less than three-fourths as long ; in semi- 

 vittatus, there are 3 lateroepicranial setae, arranged as a dorsal pair 

 and I unpaired ventral hair ; in edwardsi there are 2 pairs.. 



On the basis of larval characters, this species might have been re- 

 tained with the edwardsi group. The decision to place it in a separate 

 group was based primarily on the fact that it differed in characters 

 that were constant in the other species. 



LUDIUS SEMIVITTATUS (Say) (?) 



Figure 16, b, e 



Elater semivittatus Say, Journ. Acad. Nat. Sci. Philadelphia, vol. 3, p. 174, 



1823. — LeConte, Complete writings of Thomas Say, vol. 2, p. 113, 1859. 

 Ludius semivittatus (Say), Brown, Canadian Ent., vol. 68, p. 13, 1936. 



As stated above, this is the larva of semivittatus (Say) or of a 

 closely allied western species. The single specimen upon which this 

 study was made was collected at Walla Walla, Wash., but the range 

 of the species cannot be stated with certainty. Nothing is known of 

 the larval habits except that the available specimen was taken from 

 an alfalfa field. 



This larva strongly resembles that of Ludius sexualis Brown. Only 

 the main differences from sexualis are described since the specimen 

 is not in sufficiently good condition for an adequate detailed com- 

 parison. 



Length about 15 mm. Nasale consisting of a large median tooth 

 with a prominent lateral projection on each side near base; lateral 

 denticles appear serrate anteriorly because subnasal sclerotization is 

 closely joined with them. Subnasale consisting of transverse ridge, 

 slightly convex ventrally, serrate, with 7 to 10 short, forward-pro- 

 jecting denticles (eroded condition of specimen prevents exact count). 

 Epicranial plates with 3 lateroepicranial setae, arranged as i pair 

 with an unpaired hair farther ventrad. Coxa of prothoracic leg with 

 40 spinelike setae on anterior surface. Pleurite of first abdominal 

 segment {pi, fig. 16, b) nearly as long as sternum; on second and 

 third segments, respectively, pleurites about three- fourths and one- 

 half as long as sterna. Urogomphi (fig. 16, e) differing from 

 sexualis as follows : inner prongs {ipr) somewhat stouter than outer 

 prongs {opr), and with more pronounced tubercle {tub) on postero- 

 lateral aspect. 



The specimen examined is deposited in the U. S. National Museum. 



