294 PROCEEDINGS OF THE NATIONAL MUSEUM Vou. 113 
Discussion: In the corniculatus group, Smicronyz flavicans LeConte 
bears the strongest resemblance to S. immaculatus. The resemblance 
is particularly strong in regard to general body-shape and proportions, 
sculpturing of the prothorax and male genitalia (see figs. 78, 79). The 
two species can be instantly distinguished, however, by the color of 
the scales, which are entirely white in immaculatus but mostly various 
shades of brown and yellow in flavicans. It is of interest to note that 
the genera Ambrosia (known host genus of S. flavicans) and Iva (host 
of S. ummaculatus) are evidently closely related. 
The results of some F comparisons of S. immaculatus and S. flavi- 
cans LeConte are given below;n=15 in allsamples. A single asterisk 
indicates an F value significant at the 5 percent level; a double asterisk 
indicates an F value significant at the 1 percent level: 
F values 
Males Females 
Body length 3. 53 0. 14 
Elytra length 0. 78 0. 06 
Elytra width 5. 40* 8. 75** 
Prothorax length 3. 60 0. 83 
Prothorax width 3. 00 1. 07 
Rostrum length 7. 90** 35. 54** 
Rostrum length before antennal 11 792% 36. 64** 
insertion 
DistripuTion: Known only from the Atlantic Coastal Plain of 
North and South Carolina, with exception of one record (Rocky 
Mount, N.C.) from the Piedmont Plateau in North Carolina. The 
following specimens were examined: 
NortH CAROLINA: BRUNSWICK Co.: Holden Beach, Sept. 2 (USNM). car- 
TERET Co.: Atlantic Beach, Nov. 16 (USNM). EpGEcomBsE co.: Rocky Mount, 
March 3 (Howden). NEW HANOVER Co.: Carolina Beach, July 4, ‘“‘mid-Aug.”’ 
(Howden); Wrightsville Beach, Aug. 17 (USNM). 
SoutH CAROLINA: GEORGETOWN Co.: Pawley’s Island, Aug. 28 (USNM). 
HORRY Co.: Myrtle Beach, Aug. 6 (USNM). 
Total specimens examined (other than type series) : 86. 
Smicronyx commixtus Dietz 
FicurEs 80, 130 
Smicronyx commixtus Dietz, Trans. Amer. Ent. Soc., vol. 21, p. 160, 1894. 
Lectotype, here designated: Male, ‘Helena, Mont.,’’ MCZ 1910 (Dietz 
collection). 
Smicronyx caseyi Blatchley, Canadian Ent., vol. 48, p. 10, 1916. Lectotype, here 
designated: Male, ‘‘Indiana,’”’ Purdue University (W.8. Blatchley collection). 
Description: Rostra of both sexes rufous, moderately curved, 
squamose behind antennal insertions; substriate, sparsely and finely 
punctate before antennal insertions in male; smooth, nearly impunc- 
