1985] Miller & Davis — Insects associated with Malacothrix 549 
Results 
In general, Malacothrix incana, M. implicata, and the interspe- 
cific hybrids are visited by the same suite of generalist bees and a few 
flies, as well as small beetles and true bugs (Table 1). Many of these 
species were seen on many other flowers in a variety of families 
including Convolvulaceae ( Calystegia macrostegia subsp. macroste- 
gia [Greene] Brummit) and Crassulaceae ( Dudleya greenei Rose), in 
the Cuyler Harbor area. Because bees carry large pollen loads and 
move actively between flowers, they are probably the major pollina- 
tors of Malacothrix, although flies and beetles (as well as wasps 
which were not seen on flowers of Malacothrix on San Miguel 
Island) probably have some role in pollination. 
It is probable that the most important pollinator is the native bee 
Agapostemon texanus Cresson, the relatively large metallic green 
females of which are abundant and active, especially in the early 
morning when the flowers of both species of San Miguel Island 
Malacothrix are open and receptive for pollination. Individuals of 
A. texanus were, in general, the most commonly observed bees on 
Malacothrix (although they were more obvious due to size and 
color than many of the small halictids), and were observed flying 
between Malacothrix flowers of the same and different colors. 
However, the relatively constant wind on the island made following 
individual bees for long periods impossible, so we have no data on 
flower preference or constancy. Pollen from the hind legs of eleven 
A. texanus females collected on Malacothrix was stained with cot- 
ton blue lactophenol and compared under a phase contrast light 
microscope with pollen of M. implicata and M. incana. The major- 
ity of the pollen grains from the bees were comparable to the pollen 
of Malacothrix in size, external wall structure, and other morpho- 
logical characters although it was not possible to distinguish the 
pollen of M. incana from that of M. implicata. These observations 
are consistent with the biology of A. texanus in the laboratory 
(Roberts, 1969). 
The insects found on flowers of Malacothrix on San Miguel 
Island in May, 1984 are listed in Table 1, which also includes 
records from Cockerell (1937). All of the taxa identified to species, 
except Lopidea nigridea hirta and the Hymenoptera, are San 
Miguel Island records first published here. All these species were 
