102 Parasitic Arthropoda 



sucking species, notably Culex pipiens, have been bred repeatedly 

 without opportunity to feed upon blood. 



The effect of the bite varies greatly with different species and 

 depends upon the susceptibility of the individual bitten. Some 

 persons are driven almost frantic by the attacks of the pests when 

 their companions seem almost unconscious of any inconvenience. 

 Usually, irritation and some degree of inflammation appear shortly 

 following the bite. Not infrequently a hardened wheal or even a 

 nodule forms, and sometimes scratching leads to secondary infection 

 and serious results. 



The source of the poison is usually supposed to be the salivary 

 glands of the insect. As we have already pointed out, (p. 34), 

 Macloskie believed that one lobe of the gland, on each side, was 

 specialized for forming the poison, while a radically different view is 

 that of Schaudinn, who believed that the irritation is due to the 

 expelled contents of the cesophageal diverticula, which contain a 

 gas and a peculiar type of fungi or bacteria. In numerous attempts, 

 Schaudinn was unable to produce any irritation by applying the 

 triturated salivary glands to a wound, but obtained the typical result 

 when he used the isolated diverticula. 



The irritation of the bite may be relieved to some extent by using 

 ammonia water, a one per cent, alcoholic solution of menthol, or 

 preparations of cresol, or carbolic acid. Dr. Howard recommends 

 rubbing the bite gently with a piece of moist toilet soap. Castellani 

 and Chalmers recommend cleansing inflamed bites with one in forty 

 carbolic lotion, followed by dressing with boracic ointment. Of 

 course, scratching should be avoided as much as possible. 



Repellents of various kinds are used, for warding off the attacks 

 of the insects. We have often used a mixture of equal parts of oil 

 of pennyroyal and kerosene, applied to the hands and face. Oil of 

 citronella is much used and is less objectionable to some persons. A 

 recommended formula is, oil of citronella one ounce, spirits of camphor 

 one ounce, oil of cedar one-half ounce. A last resort would seem to 

 be the following mixture recommended by Howard, Dyar, and Knab 

 for use by hunters and fishermen in badly infested regions, against 

 mosquitoes and blackflies. 



Take 1% Ibs. of mutton tallow and strain it. While still hot add 

 % lb. black tar (Canadian tar). Stir thoroughly and pour into the 

 receptacle in which it is to be contained. When nearly cool stir in 

 three ounces of oil of citronella and 1^4 oz. of pennyroyal. 



