24 PROCEEDINGS OF THE NATIONAL IVIUSEUM vol. 121 



Material examined. — Saskatchewan: Saskatoon, Aug. 1, 1949, 

 A. R. Brooks, 14 puparia from cow manure, CNC. Washington: 

 Seattle, Sept. 15, 1942, lot no. 42-11571, det. by C. T. Greene, 4 

 larvae, 5 puparia from rotting leaves, USNM. 



Sargus (Sargus) bipunctatus Scopoli, 1763 



Figures 48, 54, 57 



Description. — Mature larvae: length 9 mm; width 3 mm. Other 

 characters as given in key to species. 



Instar no. ?: length 6.5 mm; width 2.4 mm. Differs from mature 

 larva since it lacks the vittae. 



Biology. — ^Larvae of this species have been collected from cow 

 manure. Malloch (1917) reported the larvae as being very sluggish. 



Material examined. — Maryland: Braddock Heights, Oct. 1, 

 1921, A. N. Caudell Collection, 1 larva (early instar), USNM. 



Discussion. — All data regarding description of the mature larva 

 and notes on its biology have been taken from Malloch. 



Sargus {Sargus) cuprarius (Linnaeus), 1758 



Figures 17, 62-64 



Description. — Instar no. ?: length 6.5-7.4 mm, mean 7.04 mm; 

 width 1.7-2.0 mm, mean 1.84 mm. Similar to S. decorus in this stage 

 but much smaller. 



Biology. — Larvae of this species have been collected from under 

 cow manure. 



Material examined. — Nebraska: Dunbar, Sept. 13, 1950, W. W. 

 Wirth, 39 larvae from cow manure (early instars), USNM. 



Genus Ptecticus Loew, 1855 



Of the two species listed by James (1960) for this genus, only the 

 larvae of P. trivittatas Say have been collected north of Mexico. 

 Generic characters. — -As given in key to genera. 



Ptecticus trivittatus (Say), 1829 



Figures 43, 47, 50, 51 



Description. — Mature larva: length 11.2-13.2 mm, mean 12.68 

 mm; width 3,5-3.9 mm, mean 3.76 mm; apical segment with 2 setae 

 at each corner of spiracular opening; no anal spines present; other 

 characters as given in key to species. 



Antepenultimate instar: length 12.2-15.1 mm, mean 13.67 mm; 

 width 3.0-4.5 mm, mean 3.67 mm; larvae testaceous, no visible pat- 

 tern ; body setae short, partially hidden by fine pubescence that covers 

 body; anal spines present. 



