INTRODUCTION 
Ape first American stonefly nymph was recorded by Newport? 
(34) in 1851 when he published a brief description and an 
excellent figure of Pteronarcys regalis=Pt. dorsata Say. Hagen 
(8) in 1873 describes, also, the nymph of the above species, and in 
addition to this, he describes the nymph of Pteronarcys proteus 
Newm., and mentions the nymph of Pteronarcys californica 
Newpt., from Logan River, Utah. Needham (24) in 1905 described 
briefly the nymphs of Jsoperla bilineata Say and of Leuctra 
tenella Prov., and in another paper (23) he mentions the unusual 
appearance of the nymphs of Peltoperla arcuata Ndm. Garman 
(7) describes the nymphs of three species: ‘‘No. 1,’’ ‘‘No. 2,”’ 
and ‘‘No. 3,’’ and illustrates No. 1 and No. 3 with beautiful fig- 
ures. No. 1 represents Acroneuria, probably arida Hag. No. 2 is 
not figured, but the description indicates that it is either [soperla 
or Alloperla. No. 3 is the nymph of Peltoperla sp. Smith (52) in 
1913 published a paper on the biology of Perla wmmarginata Say 
in which she describes and figures the nymph of this species, and 
in 1917 (53) she described the nymphs of the following six spe- 
cies: Pteronarcys dorsataw Say, P. californica Newpt., P. proteus 
Newm., P. biloba Newm., Pteronarcella torosa Smith=P. badia 
Hag., and Perlodes signata Hag. 
Wu (57) in 1923 gives an account of the morphology, ethology, 
and anatomy of Nemoura vallicularia Wu. This is perhaps the 
most careful and most complete biological study yet made of any 
stonefly. Needham and Christensen (29) record the following 
nymphs from Utah: Pteronarcys califormca Newpt., Pieronar- 
cella badia Hag., Acroneuria pacifica Bks., Alloperla pallidula 
Bks., and Isoperla petersoni Clsn. Seemann (51) records the 
nymphs of the following four species from California: Ptero- 
narcys princeps Bks., Acroneuria californica Bks., Isoperla 
5-punctata Bks., and Isoperla sordida Bks. Frison (6), in his ex- 
cellent paper on the fall and winter stoneflies of Illinois, describes 
and figures the nymphs of the following ten species: Taemopteryx 
nivalis Fitch, T. parvula Bks., T. (Strophopteryx) fasciata 
Burm., Allocapma vivipara Clsn., A. pygmaea Burm., A granu- 
lata Clsn., A. forbesi (?) Frison, A. mystica Frison, A. recta 
Clsn., and Leuctra claassent Frison. Muttkowsky (21) lists the 
nymphs of Pteronarcys californica Newpt., Acroneurta pacifica 
Bks., and Perla verticalis Bks., from Yellowstone Park, with data 
on the food habits of these nymphs. 
* Figures in parentheses refer to the bibliographic citations, page 116. 
