42 U.S. NATIONAL MUSEUM BULLETIN 279 



segments 1 to 4 and posterior to spinules on segments 5 and 6. DL3 

 also with 3 associated dorsal-lateral lobes (DL3a, DL3b, and DL3c, 

 fig. 33). DL3a and DL3c with few setae; DL3b with few setae plus 

 spinules, spinules more numerous on segments 4 to 6. DL3c partially 

 coalesced with DL3 in segment 5. DL3a, DL3b, and DL3c at least 

 partially coalesced with DL3 in segment 6; greatly reduced or lacking 

 posterior to segment 6. Segment 7 with transverse row of about 4 to 20 

 spinules plus setae on DLL Setae absent in some species. DL2 and 

 DL3 of segment 7 with transverse band of setae. Segment 8 with 

 transverse row of setae on DLL DL2 and DL3 with transverse band of 

 numerous setae. Segment 9 with 2 transverse rows of setae ; setae more 

 numerous in posterior row. Segment 10 without subdivisions, with 

 broad band of caudally directed, spiniform setae ; longer anterior and 

 posterior setae organized into rather discrete rows. 



Abdomen (lateral aspect, fig. 33) with 3 distinct setae-bearing lobes 

 (LLl, LL2, and LL3) on segments 1 through 8. Setae on each respec- 

 tive lobe usually decreasing in number posteriorly from about segment 

 3 to segment 8. Segment 9 normally with only 2 lateral lobes. Segment 

 10 with band of numerous spiniform setae; band slightly depressed on 

 anterior border opposite LL2 of segment 9. 



Abdomen (ventral aspect, figs. 28 and 33) with 3 distinct setae- 

 bearing lobes (VLl, VL2, and VL3) on segments 1 through 8. VLl 

 with or without fine setae on segments 1 through 5; without setae on 

 segments 6 through 9. VL3 constricted in median region, expanded 

 laterally, with group of setae on each side. Each group of setae usually 

 separated into subgroups by weakly impressed, longitudinal fold. 

 Number and size of setae and size of lobes on ventral aspect usually 

 decreasing progressively from about segment 3 to segment 9. Segment 

 9 usually with about one-half as many setae as found on anterior seg- 

 ments. Segment 10 with broad band of caudally directed, spiniform 

 setae; band narrowly discontinuous at median line. Anal opening 

 surrounded by single dorsal lobe and 2 larger ventral lobes (fig. 51). 



Species Descriptions of Omorgus Larvae 



Omorgus suberosus (Fabricius) 



Trox suberosus Fabricius, 1775, Systema entomologiae, p. 3L 



Description based on the following material. Eight larvae reared 

 from 4 adults taken at black light about 2.5 miles east of Hermiston, 

 Umatilla Co., Oreg., June 11-13, 1963, by Charles W. Baker. Ten 

 larvae reared from 3 adults collected at black light about 1.0 mile 

 south of Hermiston, Umatilla Co., Oreg., June 18, 1963, by William 



