The flower groups are divided into (i) a social set, whose flowers are in heads, spikes, or close umbels, so that insects pass from one to another without taking wing or climbing; and (2) a non-social set. The latter contains 54.4 per cent of the flowers, and is divided into Ma, I2I long-tongued bee flowers, and II adapted to birds, hawk-moths, and butterflies; and Mi, ioo shorttongued bee flowers, and 6 adapted to flies. The social set includes Mas, 82 long-tongued bee flowers; Mis, 94 short-tongued bee flowers; and Pol, 23 visited by miscellaneous short-tongued insects. The insect visits (I3,97I pollinating and 85o non-pollinating) were first distributed under MtULLER'S (8) classes. These were then divided into non-social and social sets, and the visits were distributed again under them. Of 9 cases, maxima under Hb fell under non-social Hb in 6. In 27 other cases, however, maxima under B, AB, or A always fell under the social sets. As a criterion the social or non-social condition is of primary importance, while that of nectar concealment is secondary. The flowers were also divided into a group of 23 5 plants observed before July, and one of 262 plants observed after June. Visits to these were first distributed under MtULLER'S classes. Before July there are maxima under B, AB (including Po), and A. After June there is a slight increase in Hb, including 0 and F, and a marked increase in B'. The visits were also distributed under the new classes. The early group shows maxima of the simplest flowers, Mi and white colors. These, along with Mis, decrease in the late group, which shows maxima of Ma and red (all dark colors), and a great increase in Mas. The specialization of the late group is marked by the increase of the social flowers from 38.7 to 54.I per cent. When B' as an element of the flora changes from 8.o to 28.2 per cent, in 94.2 per cent of the cases the maxima of the insect groups change from the four other dominant classes to B'. The