112 THE BIOLOGICAL REVIEW. 



FISH-KILLING HABIT OF BELOSTOMA GRISEA. 



I found this water bug, B. grisea, in our millpond yesterday, 

 August 28, 1894, firmly fastened on the back of a sucker about 

 five inches in length. The fish was propelling itself on the 

 surface of the water with the fore fins, not using the tail at all. 

 When they came to the shore I caught and separated them. I 

 kept the bug, and on returning the fish to the water it struggled 

 away on its back at the surface of the water as if paralyzed, and 

 in a dying condition. 



Milneford. C. S. Milne. 



STAINING OF WINGS OF INSECTS. 



At the request of Dr. Brodie a method of staining the veins 

 of the wings of certain insects was devised as follows : Place 

 the whole insect in a strong alcoholic solution of fuchsin, and 

 allow it to remain there for forty-eight hours. Then transfer 

 the insect to water, with a pair of fine forceps and wash it until 

 no more colour comes away, changing the water if necessary. 

 While the washed insect floats in clear water, slip a microscope 

 slide under it ; raise the slide, holding the insect on it with a 

 fine needle; separate the wings from the body with a fine 

 scapel and remove the body. With a drop or two of clear 

 water on the slide, float the wings into any desired position, 

 keeping them flat and unwrinkled, taking care to have no 

 bubbles under them. Remove any excess of water with blotting 

 paper, and allow the wings to dry. Then place a drop of thick 

 Canada balsam near them, and heat the slide over a spirit or 

 gas flame. Tilt the slide so that the now liquified balsam flows 

 over the wings; lower a cover-glass gently into position and 

 allow the preparation to cool. On examination, the veins will 

 be found red, the depth of the colouring varying with the length 

 of time of staining, the thickness of the veins, etc. The colour 

 is well retained so far as has been tried, and successful photo- 

 graphs have been made. The technique of this method is very 

 simple, but the various steps mentioned, or their equivalents, 

 must be carefully prepared, in order to obtain good results. 



Toronto. Dr. H. W. Hill. 



