134 ENTOMOLOGICAL NEWS. [May, '19 



most easily obtained by means of a wire kitchen strainer six 

 inches in diameter and of medium size mesh, with strong 

 handle. These strainers are used in households and can be 

 furnished by any hardware store. In sifting for the larvae, 

 a lump of mud the size of a fist or larger is taken from the 

 edge of the water and placed into the strainer. The latter is 

 then gently shaken, at the same time immersing it in the water 

 near the edge. The earthy constituents are washed through 

 the wire meshes and the Tabanid larvae become visible. This 

 process is repeated until it gives positive results, which is near- 

 ly always the case within less than half an hour. If the 

 larvae are not found readily in one place, they will often be 

 present in another place only a few feet distant. It is often 

 found convenient to seize bundles of sod by the roots and 

 shake them with water in the strainer until the earth is washed 

 of¥. Frequently the larvae are found clinging to the grass 

 roots. Wherever soft mud is exposed to the surface directly 

 adjoining the water, it should be put through the strainer and 

 it will usually contain some larvae. Even sandy and muddy 

 banks without any vegetation will frequently yield an abun- 

 dance of larvae of Tabanus and Chrysops. At ponds where a 

 rich green vegetation of Lemna and aquatic weeds is present, 

 the half-decaying masses which border the edge of the mud un- 

 derneath may contain larvae. Brooks with coarse sand or 

 gravel are not favorable because the coarse sand does not pass 

 through the meshes of the strainer and therefore the larvae are 

 often overlooked or injured. Generally, the larvae are located 

 only a few inches from the surface, but may be found to a depth 

 of one foot, and in some localities even deeper. In places where 

 the water has receded, owing to dry weather, the larvae will of- 

 ten follow the receding water and be found at the new edge, but 

 if the ground retains some moisture they may be looked for all 

 over the formerly inundated region. Ponds or brooks with a 

 definite permanent border give better results than indefinitely 

 bordered swamps, wet meadows, etc. One has always to bear 

 in mind that the larvae are air-breathers and as such may scat- 

 ter in swampy regions with low water level over wide areas, 

 while in all localities where the water maintains a certain level, 



