64 
Psyche 
[June 
brium are primary foodplants of E. ausonides and that the 
eggs are laid and the larvae feed largely on the flower buds 
and seed pods. The suitability of other plants as food re- 
mains uncertain. The literature on North American 
Euchloini too often refers simply to “Cruciferae”. In Con- 
necticut we have found that the larvae of Anthocaris midea 
(Hbn.) regularly die on some members of the family, even 
though wild females occasionally oviposit on them. 
4. Pieris rapae (L.). On 9 July 1949, at Nederland, 
females were seen ovipositing on Thlaspi arvense L. 
[R.C.R.], and on the 11th a female oviposited on a large 
Sisymbrium altissimum L. [R.C.R.]. The ova were notably 
white when laid (see P. protodice , below). In general, P. 
rapae is still uncommon in the mountains, perhaps in part 
because it may not thrive on native Cruciferae, and the 
weedy forms are not very abundant there. In spite of the 
presence of P. rapae, P. napi is by far the commonest 
Pieris above 7000'; it is believed to have been largely 
extirpated from New England by P. rapae (Scudder, 1889, 
p. 1198). The much greater success of P. napi in the Rocky 
Mountains, where both species oviposit on Thlaspi (see P. 
napi, below), suggests that Thlaspi may be nutritionally 
inadequate or poisonous for P. rapae. 
5. Pieris protodice Bdv. & Lee. There is no unanimity 
in the name for the Colorado population of low and middle 
altitudes. However, I am satisfied that it cannot be a 
species distinct from eastern protodice. Near and above 
timberline there is a very striking form ( calyce Edw.?), 
which may be a separate species. P. protodice females 
were seen at Nederland on 9 July 1949, ovipositing on 
Sisymbrium altissimum L. [R.C.R.] and Thlaspi arvense 
L. [R.C.R.]. The new ova were distinctly yellowish, con- 
trasting with some of P. rapae taken at the same time 
(see above) . 
6. Pieris napi (L.) . On 5 July 1949, at Eldora in Boulder 
County, Colo., a female was seen laying several ova on 
tiny seedlings of Thlaspi arvense L. [R.C.R.]. The new 
eggs were white. At Eldora, on 28 July, many Thlaspi 
plants beside a dirt road were examined. Fifty-six ova and 
a few young larvae of P. napi were found. Fifty-one ova 
