318 THE AMERICAN MONTHLY [Oct. 



tion. Any pellicle which forms on the surface is removed 

 with blotting- paper. The staining- is accelerated by the 

 addition of 25 per cent of borax to the methyl blue solu- 

 tion. The time required for staining- blood preparations 

 is about half an hour. On the addition of borax, however, 

 only ten minutes is necessary for org-anisms of low devel- 

 opment, without borax fifteen minutes. Flag-ellates take 

 long-er than blood. The objects are fixed either by being- 

 passed thrice throug-h a flame, or are immersed for half an 

 hour in absolute alcohol. Flag-ellates are fixed by immer- 

 sion in hot sublimate alcohol (saturated aqueous sublimate 

 solution, 2 parts, absolute alcohol, 1 part), and washing-with 

 63 per cent iodine alcohol. The results with bacteria are 

 not yet satisfactory. 



BIOLOGICAL NOTES. 



Parasites of House Fly.^ — A parasite is extremely com- 

 mon on the house fly in Bermuda. It is I believe a species 

 of Trombidium. Those that I noticed could move rapidly 

 over the body of the fly, and when disturbed concealed 

 themselves under the halteres. At other times they ap- 

 peared to usually attach themselves to the abdomen of the 

 host. The parasite was of a red color. Another curious 

 parasite which I observed on the house fly in Bermuda was 

 a small red ant. This creature attaches itself to the tar- 

 sus of the fly by means of its mandibles. It was a matter 

 of common observation to see flies on the wing- with these 

 small ants attached. On one occasion I diseng-ag-ed the 

 ant and placed it on a table. It remained quiet until a fly 

 came within suitable distance, when it made a rush, and 

 was carried off cling-ing- to the leg- of the fly. I believe the 

 reason of attack was made for the purpose of finally eating- 

 the fly. The ant held on until its host became exhausted, 

 and then attacked a more vital spot than the foot,and killed 

 it. These ants eat the soft parts out of a dead cockroach 

 in a very short time. The Empusa muscae is a well-known 

 fung-oid parasite of the housefly. The fung^us "rests" 

 during the hot weather in Bermuda, but during- the cool 



