150 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, III 



THE LUDIUS LIMONIIFORMIS GROUP 

 Figures ii, h; 29 

 KEY TO SPECIES 



With 5 or more "teeth" laterally on dorsum of ninth abdominal segment 

 {to, fig. 29, b) ', larva rarely exceeding 20 mm. in length; west of Lake 

 Superior limoniiformis (Horn) (?) (p. isi') 



With 4 "teeth" laterally on dorsum of ninth abdominal segment {to, fig. 29, 

 e) ; larva might exceed 30 mm. in length; eastern North America. ... 

 cylindriformis (Herbst) (?) (p. 156) 



This group is represented in the larval stage by two species that 

 are not positively identified, but which are believed to be limoniiformis 

 (Horn) and cylindriformis (Herbst), 



These larvae are soil inhabiting, apparently preferring relatively 

 moist situations. Both species are minor pests of cultivated plants. 



Liidius limoniiformis and L. cylindriformis larvae are easily sepa- 

 rated and might eventually be placed in different species groups, but 

 they possess many characters in common and are not closely allied 

 to any other of the known Ludius larvae. The body is relatively long 

 and narrow, most of the abdominal segments being as long as wide. 

 Eyes are absent and the presternum of prothorax is undivided. Other 

 important characters are found in the urogomphi (fig. 29, b-e), the 

 dorsum of the ninth abdominal segment (fig. 29, b, e) — especially the 

 sharp marginal "teeth" {to) and the lack of a mediodorsal groove — 

 and the nasale (fig. 29, a). 



The larvae of the limoniiformis group are light brown or yellow 

 brown. Caudal notch small, subcircular or subovate, nearly closed 

 posteriorly, Urogomphi bifid ; inner prong broad, with i or more 

 tubercles on posterior aspect ; tip of outer prong sharp, inclined in- 

 ward or forward. Ninth abdominal segment (fig, 29, b, e) with 4 or 

 more prominent, sharp "teeth" {to) on lateral aspects of dorsum and 

 with 4 unpaired setae on the central dorsal area, but without a median 

 longitudinal groove. Nasale (fig. 29, a) with tridentate tip, lateral 

 denticles small and frequently eroded off. Frontoclypeal area truncate 

 posteriorly. Second joint of antenna bearing i "sensory" appendix. 

 Basal joint of labial palpus without setae. Eyes absent. Gula short, 

 narrow. Presternum of prothorax undivided. Episterna of meso- 

 thorax and metathorax with several spinelike setae. Abdominal 

 mediotergites with some of prominent setae paired (usually 2 pairs) 

 or in a semipaired arrangement, and in second to fifth segments with 

 transverse branches of impressions reaching to or nearly to the mid- 

 dorsal suture. First 8 abdominal segments with small pleurites. 



