36 Poisonous Arthropods 



teristic itching irritation of the mosquito bite; and in a short time 

 there appeared reddening and typical swelling. This was usually 

 much more severe than after the usual mosquito bite, and the swell- 

 ing persisted and itched longer. This was because by the ordinary 

 bite of the mosquito most of the yeast cells are again sucked up, 

 while in these experiments they remained in the wound. These 

 experiments were repeated a number of times on himself, his assistant 

 and others, and always with the same result. From them Schaudinn 

 decided that the poisonous action of the mosquito bite is caused by 

 an enzyme from a commensal fungus. These conclusions have not, 

 as yet, been satisfactorily tested. 



Relief from the effect of the mosquito bite may be obtained by 

 bathing the swellings with weak ammonia or, according to Howard, 

 by using moist soap. The latter is to be rubbed gently on the punc- 

 ture and is said to speedily allay the irritation. Howard also quotes 

 from the Journal of Tropical Medicine and Hygiene to the effect that 

 a few drops of a solution of thirty to forty grains of iodine to an ounce 

 of saponated petroleum rubbed into the mosquito bite, or wasp sting, 

 allay the pain instantaneously. 



Methods of mosquito control will be discussed later, in consider- 

 ing these insects as parasites and as carriers of disease. 



STINGING INSECTS 



The stinging insects all belong to the order Hymenoptera. In a 

 number of families of this group the ovipositor is modified to form a 

 sting and is connected with poison-secreting glands. We shall 

 consider the apparatus of the honey-bee and then make briefer refer- 

 ence to that of other forms. 



Apis mellifica, the honey bee The sting of the worker honey- 

 bee is situated within a so-called sting chamber at the end of the 

 abdomen. This chamber is produced by the infolding of the greatly 

 reduced and modified eighth, ninth and tenth abdominal segments 

 into the seventh.* From it the dart-like sting can be quickly ex- 

 serted. 



The sting (fig. 25) is made up of a central shaft, ventro-laterad of 

 which are the paired lancets, or darts, which are provided with sharp, 

 recurved teeth. Still further laterad lie the paired whitish, finger- 



*It should be remembered that in all the higher Hymenoptera the first ab- 

 dominal segment is fused with the thorax and that what is apparently the sixth 

 segment is, in reality, the seventh. 



