1939] 
Immature Trichoptera 
9 
IMMATURE NORTH AMERICAN TRICHOPTERA 
By Margery J. Milne 
Randolph-Macon Woman’s College, 
Lynchburg, Va. 
Several keys to the larvae and two to the pupae of North 
American Trichoptera are already available 1 but none of 
them summarizes recent study of adequate material, and all 
but one are based either directly or indirectly on tables pre- 
sented by European workers. 
A search for family and subfamily characters in North 
American caddis larvae and pupae has yielded the two keys 
below. Since the pupal stage is much less completely known 
than the larval, the key to the former is more artificial than 
that to the latter, especially with respect to members of the 
families Odontoceridae and Sericostomatidae. To somewhat 
offset this disadvantage, a very useful list of spur formulae 
is appended, summarizing the known information on this 
character. 
!1901. Betten, C. in Bull. 47, N. Y. State Mus. pp. 563-564. A larval 
key compiled from European papers by Klapalek and Struck. 
1915. Krafka, J. Jr. in Can. Ent. 46: 217-225. Original keys to 
larvae, guided by Ulmer’s 1909 European work. 
1921. Lloyd, J. T. in Bull. 21, Lloyd Lib. (Ent. Ser. 1) p. 15. A 
slightly modified translation of Ulmer’s 1909 key, larvae only. 
1921. Lutz, F. E. in Field Book of Insects (Putnam) pp. 58-60. A 
modification of Betten’s 1901 key to larvae. 
1925. Comstock, J. H. in Introduction to Entomology (Comstock) 
p. 560. A modification of Lloyd’s 1921 key to larvae. 
1926. Essig, E. O. in Insects of Western North America (Macmillan) 
p. 175. A modification of the key to larvae in Lloyd 1921 and 
Comstock 1925. 
1926. Sibley, C. K. in Bull. 27, Lloyd Lib. (Ent. Ser. 5). An appar- 
ently original key to the pupae of species found on the Lloyd- 
Cornell Reservation, N. Y. 
1933. Brues, C. T. & A. L. Melander in Bull. 73, Mus. Comp. Zool. 
Harvard, pp. 195-197. A modification of Krafka’s 1915 key 
to larvae. 
1934. Betten, C. in Bull. 292, N. Y. State Mus. pp. 117-123, the larval 
key a copy of Krafka’s 1915 work, the pupal key from 
Ulmer’s 1909 key. 
