67 
DIPT Ell A (TWO-WINGED FLIES). 
the hours from 8 o’clock till noon and from about 4.30 till sunset 
are usually the best for collecting. In England the best months for 
collecting are May, June, and July; but many species are to be 
found until late in September, while others occur in April or even in 
March : much of course depends upon the year, the season being 
sometimes a full month earlier or later than usual. 
The following hints on collecting have been kindly furnished by 
Lieut.-Colonel J. W. Yerbury, who has had great experience in 
collecting Diptera both in this country and abroad :— 
“ Diptera are to be found everywhere. Still, the following points 
should always be considered :— 
“ Locality. —In temperate climates virgin soil is best, with a south 
or west aspect for choice. 
“In the tropics shelter from the prevailing wind is the most 
important point. 
“ Shelter, however, is an important factor everywhere, and the 
line taken should be selected with due regard for the direction of 
the wind. 
“ Habits. —The habits of the various families differ greatly, and, as 
a natural consequence, their favourite localities vary also. Before 
discussing these in detail, it may be advisable to enumerate some of 
the general attractions for the Order. 
“ Flowers. _Some flowers are particularly attractive to Diptera, 
and these are as a rule white or yellow in colour. 
“ Jn England the flowers of the following may be enumerated as 
specially attractive: common and Portugal laurel, holly, black¬ 
thorn, hawthorn, bramble, plane, barberry, and at times rhododendron 
and dog-rose ; but the attraction of the two latter does not as a rule 
last long. Probably all these are equally attractive in Europe, and 
to them may be added dane-wort (Sambucus ebulus). 
“ In the tropics Diptera should be looked for on the flowers of 
several palms and various species of Bher-trees (Zizyphus), etc. 
“Sugar, as applied by Lepidopterists, has not as a rule much 
attraction, Still, occasionally it is attractive to Calypterate Muscicla ), 
