CHAPTER XXXIV 



Insect Poisoning and Miscellaneous Notes on the Transmission of Diseases 



by Insects 



W. Dwight Pierce 



In the various lectures which have preceded this one, most of the 

 large groups of disease-carrying insects have been discussed in full but 

 there are a number of cases of carriage of disease by insects of other 

 groups and there are many cases of insect poisoning which have not been 

 covered. As a matter of fact the majority of species of insects which 

 are chargeable with poisoning have not been mentioned. 



In the present course of lectures, for convenience, all arthropods have 

 been considered under the popular term insects. The general public does 

 not discriminate between a spider, a scorpion, a mite, a tick, and an 

 insect as far as the general nomenclature is concerned. In fact the disease 

 relationship in these different groups are so similar that any discussion 

 of them from a sanitary standpoint should include all of the groups 

 Virhich belong to the Phylum Arthropoda. The scorpions belong to the 

 order SCORPIONIDEA, the spiders to the order ARANEAE, and the 

 mites and ticks to the order ACARINA, all in the class ARACHNIDA, 

 characterized by eight legs. It is also well to consider the very nearly 

 related class CHILOPODA, which includes the centipedes and millipedes 

 with one or two pair of legs to each segment. The insects all belong to 

 the INSECTA, characterized by six legs. 



SCORPION POISONING 



There is great popular fear of the sting of the scorpion. These 

 creatures are found largely in semitropical and tropical countries and 

 are possessed of a tail with a sting at the tip. The effect of the poison- 

 ing is more or less severe and in some cases is fatal. The method of 

 stinging is to bring the tail forward over the body so that the curved 

 spine on the last segment penetrates the skin and inflicts the wound. 

 On either side of this curved barb is an opening from which the duct 

 from the poison gland discharges the venom. Very little has been done 

 on the toxicity of the poisons of the various species of scorpions. Castel- 

 lani and Chalmers have summarized in a few pages the subject of scorpion 



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