DIPTERA (two-winged FLIEs). 67 



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 

 Lieiit.-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. 



"In 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. 



" Suga7', as applied by Lepidopterists, has not as a rule much 

 q,ttraction, Still, occasionally it is attractive to Calypterate Muscidce, 



