g6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



dentate. Frontoclypeal area bluntly rounded posteriorly. Second joint 

 of antenna bearing i "sensory" appendix. Without setae on basal 

 joint of labial palpus. Eyes present. Gula elongate and narrow. 

 Mandible with relatively small retinaculum set in slight depression. 

 Presternum of prothorax divided into 3 pieces. Episterna of meso- 

 thorax and metathorax without spinelike setae. Mediotergites of first 

 to eighth abdominal segments with prominent setae unpaired (some- 

 times 2 most medial setae in semipaired arrangement), and transverse 

 branches of impressions rarely exceeding one-half the distance from 

 the longitudinal branches to the middorsal suture. On first to seventh 

 abdominal segments sternum usually divided by lateral sutures into 3 

 pieces, pieces usually not completely separated. Anal aperture some- 

 what T-shaped. 



LUDIUS ROTUNDICOLLIS (Say) 



Figures 14, ;; 21, a, b, e-h 



Elater rotundicollis Say, Ann. Lyceum Nat. Hist. New York, p. 259, 1825. 

 Corymbites rotundicollis (Say), LeConte, Trans. Amer. Philos. Soc, new 



ser., vol. 10, p. 440, 1853. 

 Ludius rotmidicollis (Say), Van Dyke, Proc. California Acad. Sci., vol. 20, 



p. 427, 1932. 



According to Van Dyke (1932, pp. 404, 427-428) this species occurs 

 in both the "Atlantic States and Pacific States," the more typical 

 rotundicollis being in the East and the subspecies nigricans (Fall) 

 and diversicolor (Eschscholtz) in the West. In the present study, 

 larvae identified as rotundicollis (Say) have been obtained from 

 the extreme eastern and the extreme western parts of the United 

 States. The specimens from the two regions are very similar, but 

 sufficiently different in structure to suggest specific distinction. 



"Eastern species." — Larvae have been examined from Pennsyl- 

 vania, Maryland, and New York State. The collectors' notes reveal 

 that some specimens were taken from under bark on the trunk of 

 an elm tree and others were observed attacking spiders in silken 

 cocoons. Knull (1932, p. 43) reports the larvae as predaceous upon 

 the larvae of cerambycids inhabiting the outer bark of numerous 

 living deciduous trees. There are no records on the time of pupation, 

 but Blatchley (1910, p. 768) observed the adults to hibernate beneath 

 logs on sandy hillsides. 



The larva of the "eastern species" may be distinguished from that 

 of the "western species" by the following characters: Slightly paler 

 in color, fewer setae, somewhat weaker punctation, a much more 

 prominent posterior "tooth" {to, fig. 21, /) on the lateral margins 



