364 
Psyche 
[September-December 
had been laid on both upper and lower surfaces of rosette leaves, 
lower surfaces of the (oppressed ) cauline leaves (often near the 
point of attachment, as was also true on Barbarea verna ), and on 
stems. One larva (3rd instar) was found, and two ovipositing 
females were observed. On 22 May, 16 additional ova and 5 larvae 
were found at the same spot on the same plants, which were now 
mature and beginning to set fruit. Abundant evidence of larval 
feeding was found on the rosettes and lower cauline leaves, but the 
flowers and siliques were undamaged. Fourteen plants of flowering 
Barbarea orthoceras Ledeb. were found in a grassy meadow 0.7 mile 
up the canyon, within the area where adult P. napi had been seen, 
but no ova, larvae, or feeding damage could be located on them. 
Lang Crossing , Nevada County. — This population is at about 4500 
feet in the South Yuba River canyon, at or near the upper altidudinal 
limit of Sierran P. napi; it is also univoltine. On 22 May 1974, 
3 ova of P. napi were found in a stand of 30 immature Arabis glabra 
and none on 20 flowering Barbarea orthoceras growing immediately 
adjacent to them. On 2 June the same stand was again searched, 
producing 11 ova of P. napi , 20 of P. rapae Linnaeus, 3 of i. sara 
and 2 of Anthocaris lanceolata Lucas from A. glabra, and 8 of 
A. sara from B. orthoceras. An additional 34 ova of P. napi were 
collected from A. glabra elsewhere in the vicinity. Four larvae of 
P. napi were found feeding on rosette leaves of A. glabra, and two 
of A. sara on inflorescences and siliques of B. orthoceras. On 26 June 
four mature A. sara and two immature A. lanceolata larvae were 
found on siliques of A. glabra and one mature A. sara larva on 
siliques of B. orthoceras. Many A. glabra plants showed feeding 
damage to the rosettes, but only seven P. rapae larvae were found; 
probably most napi had already pupated. Pieris rapae, which is 
multivoltine, was flying in abundance at Lang Crossing on 19 July. 
Despite the large number of Pierid species and individuals, the 
visible impact of feeding on the Crucifers at Lang Crossing was 
quite small. In particular, Arabis glabra plants often produced 
several hundred siliques on leafy, two- to four-foot stems. 
Discussion 
There are ten species of obligate Crucifer-feeding Pierids in 
California, occurring in various combinations at different localities. 
Some of these are spring-univoltine, a few are spring-bivoltine, and 
some are multivoltine. How they partition the available Crucifers 
among themselves may shed valuable light on the broad problems 
