110 
Psyche 
[April 
Naturally they occur throughout the fiower-blooming season 
and are most abundant in summer when the most of plants are 
in vegetation. The butterflies form a long low curve, March 10 — 
November 7, and have a maximum of 80.5 per cent July 7-22, 
87 per cent flying in July. Pronuha is perhaps the only lepidopter 
whose season is correlated with, and indicates the presence of, 
particular kinds of flowers. Butterflies often have food plants 
which are not entomophilous. Given their food plants and 
long-tongued bee flowers, they could get along pretty well. 
Diytera , — The Diptera fly from March 9 to November 6 
and show a maximum of 59.2 per cent July 22-27, 67 per cent 
flying in June. The Nematocera, April 6 — October 18, have a 
maximum of 50 per cent May 25 — June 2, 90 per cent flying in 
May. The Stratiomyidse, April 21 — August 26, have a maximum 
of 70 per cent May 18-22, 80 per cent flying in May. The Em- 
pididse, April 10 — October 8, have a maximum of 72.2 per cent 
April 30 — May 4, 88.8 per cent flying in May. The Syrphidse, 
March 10 — November 6, have a maximum of 67.5 per cent 
June 10-11, 80 per cent flying in May. The maximum of the 
lower SyrphidiB is May 12-15, while that of the higher is June 
10-11. The Muscoidea, March 9 — November 6, show a maximum 
of 69.2 per cent July 26-27. They are 51.6 per cent of the 
Diptera observed on flowers. The Bombyliidse, March 21 — 
October 29, have a maximum of 60.7 per cent August 21, 67.8 
per cent flying in August. The Conopidse, April 10 — November 
3, have a maximum of 76.9 per cent July 4 — August 8, 84.6 per 
cent flying in August. 
The flight of Diptera is evidently associated with that of 
the insects on which they are parasitic, or the presence of the 
plants, or other food, on which the larvae feed. None have a 
primary relation to flowers. Their adaptations to flowers are 
only to such flowers as happened to be present during their 
flight. Not more than 18 per cent have siphonate proboscides. 
Hymenoptera (ex. bees). — The lower Aculeata fly from 
March to November and have a maximum of 86.8 per cent 
July 25-27, 91.7 per cent flying in July and 90.6 per cent in 
