184 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



KEY TO SPECIES OF CRYPTOHYPNUS 



1. Urogomphal prongs subequal (fig. 38, e, g) ; eastern North America 



abbreviatus (Say) (p. 185) 



Inner prongs of urogomphi longer than outer prongs (fig. 38, /;. i) 2 



2. Nasale (n, fig. 38, d) with several small denticles on each side of base of 



median tooth; western North America funebris Candeze (p. 185) 



Nasale (n, fig. 38, b) tridentate, lateral denticles sometimes absent 

 through erosion (the riparius group, p. 184) 3 



3. From Europe riparius (Fabricius) 



From North America 4 



4. Basal segment of labial palpus with i seta ventrally sanborni Horn 



Basal segment of labial palpus without setae nocturnus (Eschscholtz) 



THE CRYPTOHYPNUS RIPARIUS GROUP 

 Figures id, g; 38, b, h, i 



Included in this group are riparius (Fabricius), nocturnus (Esch- 

 scholtz), and sanborni Horn. All live in the soil. C. nocturnus is 

 reported by King (1928, pp. 703-704) as an important pest of grain 

 crops in Saskatchewan, and Evans (1921) suggests that riparius 

 might injure field crops in Scotland. 



This is a very homogeneous group, well characterized by the 

 urogomphi and caudal notch (fig. 38, h, i) and by the nasale and sub- 

 nasale (fig. 38, b). 



These larvae seldom exceed 13 mm. in length. The inner prongs 

 of the urogomphi are about twice as long as the outer prongs; the 

 tips of the outer prongs turn slightly inward. The large, U-shaped 

 caudal notch is not narrowed posteriorly except in a few atypical 

 specimens. In the tridentate nasale, the lateral denticles are often 

 weakly developed and sometimes are eroded away, giving a unidentate 

 appearance. The frontoclypeal area is broadly rounded posteriorly. 



Material used in the study of the group. — C. riparius (Fabricius) : 

 Eight larvae were examined. These were from Denmark (5), Fin- 

 land (i), Russia (i), and Ireland (i). The specimens studied are 

 believed to be reliably named, because the larva of this species is well 

 known in Europe and some of the available material was used by 

 K. L. Henriksen (1911) in his description of this species. (B.M. and 

 U.S.N.M.) 



C. nocturnus (Eschscholtz) : Thirteen examples were studied, in- 

 cluding the exuviae of four reared specimens. The reared adults were 

 identified by W. J. Brown, of Ottawa. 



10; Barnwell, Alberta; June 6, 1935; 2 adults emerged Aug. 8 and Aug. 9, 

 1935; R. Glen. (C.N.C.) 



