362 MOSQUITOES OF NORTH AMEEICA 



" It would be a mistake to believe that these dwarf individuals of Stegomyia 

 are less aggressive and sanguinary than those of normal stature. They behave 

 in a precisely similar manner ; their bites are not less painful, as I have had fre- 

 quent occasion to prove/' 



A study of the question of mosquito bars or canopies, both for indoors and 

 out-of-doors, has been made by Dr. F. Arnold, the District Medical Officer of 

 Health, Northern Transvaal, and he has published an interesting article on the 

 subject in The Transvaal Agricultural Journal for October, 1907, pages 13-15. 

 He illustrates the mesh of different nettings purchased in Pretoria, labeling a 

 netting with a mesh 1 mm. in width as good, one of 2 mm. as doubtful, and one 

 of 3 mm. as bad. These nettings were tested by stretching them over the mouths 

 of three large pill-boxes, and in each pill-box was put a known number of live, 

 uninjured mosquitoes. The boxes were placed on a chair alongside his bed, 

 where they remained aJl night, with the idea that by placing the mosquitoes 

 near a sleeper they would be anxious to get at him, and the natural conditions 

 existing in a bedroom would be imitated ; that is, there would be a mosquito 

 and a sleeper separated by a net. The conclusions coincided with those above 

 indicated. Doctor Arnold continues his directions in the f ollowinsr words : 



-'o 



" In this country the bell-shaped bedroom mosquito net is almost always 

 used ; box-shaped nets are rarely seen. In Eastern countries the box-shaped net 

 is generally used fixed on to a large four-posted bed ; such an arrangement has 

 the great advantage that the net can be drawn tight and there is within it so 

 large a space for the sleeper that his limbs, if uncovered, are not likely to come 

 in contact with the net. 



" Frequently the bell net has too small a ring at the top and the netting is not 

 sewn on to the calico which closes the ring, but is gathered-up above it by a 

 running thread ; such an arrangement causes folds to be formed in the net above 

 the ring and through the grooves of these folds mosquitoes enter freely. Again, 

 the net is often allowed to hang loose on the bed or it is drawn over the whole 

 bedstead on to the ground. When hanging loose it affords very little protection, 

 for it will, during the night, certainly come in contact with the face, arms, etc., 

 which will be bitten through the net. If placed right over the bedstead then its 

 lower margin must be heavily-weighted with a long and continuous sand bag, 

 and every care must be taken to drive away mosquitoes which may be sleeping 

 on the dark under side of the mattress ; in out-lying districts white ants would, 

 in one night, make short work of net and sand bag if lying on a mud floor. 

 How, then, should a net be made and arranged ? 



" Proceed as follows : Obtain a ring of wood or iron, in diameter two and a 

 half to three feet ; close it with a piece of stout calico ; on this calico, around the 

 circumference of the ring, sew the mosquito net very carefully, using netting 

 of the mesh shown as No. 1. Suspend the net to the ceiling in the usual way. 

 Next arrange the bedding as is done on board ship; that is to say, take the 

 upper sheet, blanket and counterpane and fold the margins inwards at the sides 

 and at the foot ; all the bedding which will cover the sleeper will then lie on 

 the top of the under sheet. Now tuck the mosquito net under the mattress all 

 round, drawing it tight. On going to bed draw out the net at one side, creep 

 in under it, and carefully tuck it back under the mattress. The sleeper is now 

 in a cage ; it does not matter how much he kicks about the net will remain true, 

 and, provided that a fair-sized bed is used, there is not much risk of an unclothed 

 part of the body touching the net. For use on the veld many kinds of stretchers, 

 etc., have been devised. The writer has used a folding stretcher which carries 



