74 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



nal segments the transverse branches of impressions reach from two- 

 thirds to four-fifths distance from longitudinal branches to middorsal 

 suture. 



Material used in study. — The only material available was the larval 

 exuviae of two reared specimens and two whole larvae that by com- 

 parison were believed similar. The reared adults were identified 

 originally by R. H. van Zwaluwenburg and checked by W. J. Brown, 

 of Ottawa. 



LUDIUS PUDICUS Brown 



Figure 17, d, e 

 Ludius piidicus Brown, Canadian Ent., vol. 68, p. 183, 1936. 



This western species is known to inhabit British Columbia, south- 

 western Alberta, and the State of Washington. 



Nothing is known of the larval habits since the only specimens avail- 

 able for study were reared from eggs laid in captivity. 



The larva is well characterized by its very large, corniform outer 

 prongs of urogomphi {opr, fig. 17, d, e), which are at least 3 times as 

 long as the inner prongs. The largest larva examined was 17 mm. 

 long, but mature specimens might be larger. Each gena bears only 

 3 lateroepicranial setae, with an additional seta farther dorsad and 

 another farther anterad. First segment of antenna two-thirds as 

 wide as long and about 3 times as long as second segment. Coxae 

 of prothoracic legs bearing up to 25 spinelike setae on each anterior 

 surface; coxae of mesothoracic and metathoracic legs with up to 35 

 spinelike setae. On each mediotergite of second to eighth abdominal 

 segments the transverse branch of impression reaches about one-half 

 of the distance from the longitudinal branch to the middorsal suture. 



Urogomphi (fig. 17, d, e) well developed. Inner prong {ipr) short, 

 projecting caudodorsad and slightly mediad with sharp, horny tip 

 curving upward and slightly forward ; bearing 2 large setae, i ventro- 

 laterally near base, other ventrally at base; a few minute hairs on 

 prong. Outer prong {opr) corniform, very large and strong; about 

 as long as undivided part of urogomphus and at least 3 times as long 

 as inner prong; projecting caudodorsad and slightly laterad, with 

 sharp horny tip curving forward; 2 prominent setae, i on antero- 

 lateral aspect about halfway along prong, other (longer) laterally at 

 base of prong; several minute setae scattered over prong, the most 

 noticeable on the anteromedial aspect in distal half of prong. Un- 

 divided part of urogomphus with i prominent seta and i or 2 minute 

 setae, all on ventral surface. 



Caudal notch {en) large, U-shaped or V-shaped. 



