go SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



LUDIUS GLAUCUS (Germar) 



Figures 13, /, h; 16, a 



Diacanthiis glauciis Germar, Zeitschr. fur die Ent., vol. 4, p. 76, 1843. 

 Hadromorphus siinilissimus Motschulsky, Bull. Soc. Moscou, vol. 32, p. 374, 



1859. 

 Liidius glaucus (Germar), Brown, Canadian Ent., vol. 68, p. 135, 1936. 



The distribution of this w^estern species is indicated by Brown 

 (1936c, p. 135) as extending from Utah to CaHfornia and north to 

 southern Alberta and the Okanagan Valley of British Columbia. The 

 author has found the larvae in grain fields in southwestern Alberta 

 and along the foothills of the Rocky Mountains as far north as 

 Calgary. Essig (1926, p. 394, "in flatus") reports the species in 

 Arizona and New Mexico. Under the name of in flatus Say, the larva 

 has been recorded as an important pest in Washington, Oregon, Idaho, 

 and Montana. The crops most frequently injured are wheat, corn, 

 and potatoes. Lane (1925, p. 91) reports that the species inhabits 

 areas where the annual rainfall exceeds 15 inches, and Hyslop (1915a, 

 p. 10) describes the typical native habitat as one of bunchgrass 

 {Agropyron spicatuni) and June grass (Poa secunda) but lacking 

 in sagebrush. 



According to Hyslop (1915a, p. ii), the normal larval period is 3 

 years, pupation occurring in late June and early July. However, a 

 specimen collected in May and reared by the writer did not pupate 

 until August. The oval pupal cell measured 13 mm. by 6 mm. The 

 transformation to the adult state is completed within 2 or 3 weeks 

 and the beetles overwinter in their pupal chambers. 



Distribution and slight differences in sculpture serve for the dis- 

 tinguishing of the larvae of glaucus and the closely related inflatus. 



Description of "mature" larva. — Length 16 mm., greatest breadth 

 2.6 mm. on fourth and fifth abdominal segments. A fully distended 

 larva measured 18.5 mm. Body robust; with large membranes on 

 lateral aspect; all segments broader than long; head and ninth ab- 

 dominal segment about three-fourths greatest body width. Dorsum 

 pale yellow (pale "yellow ocher," Ridgway, 1912) to very light 

 brown ; venter slightly paler. Dorsum bearing fine punctures, increas- 

 ing in abundance on the more posterior segments. 



Head subquadrangular with arcuate sides, flattened above and below. 



Frontoclypeal region with posterior part extending backward to or 

 almost to foramen magnum, truncate posteriorly. Two prominent 

 anterior nasosulcal setae on each side of base of nasale. Nasale uni- 

 dentate, terminating sharply when uneroded. Subnasale consisting 



