Hexapoda, or True Insects 27 



Clarke's column had been destroyed. The perivascular sheaths 

 were crowded with small round cells and the meninges were con- 

 gested. Some of the cells of the anterior horn were swollen and the 

 nuclei eccentric ; chromatolysis had occurred in many of them. 



As for treatment, Castellani and Chalmers (1910), recommend 

 bathing the part well with a solution of ammonia (one in five, or one 

 in ten). After bathing, apply a dressing of the same alkali or, if 

 there is much swelling and redness, an ice-bag. If necessary , hypo- 

 dermic injections of morphine may be given to relieve the pain. 

 At a later period fomentations may be required to reduce the local 

 inflammation. 



THE HEXAPODA OR TRUE INSECTS 



There are a number of Hexapoda, or true insects, which are, in 

 one way or another, poisonous to man. These belong primarily 

 to the orders Hemiptera, or true, bugs; Lepidoptera, or butterflies 

 and moths (larval forms) ; Diptera, or flies ; Coleoptera, or beetles ; 

 and Hymenoptera, or ants, bees, and wasps. There are various ways 

 in which they may be poisonous. 



1. Piercing or biting forms may inject an irritating or poisonous 

 saliva into the wound caused by their mouth-parts. 



2. Stinging forms may inject a poison, from glands at the caudal 

 end of the abdomen, into wounds produced by a specially modified 

 ovipositer, the sting. 



3 . Nettling properties may be possessed by the hairs of the insect. 



4. Vescicating, or poisonous blood plasma, or body fluids are 

 known to exist in a large number of species and may, under excep- 

 tional circumstances, affect man. 



For convenience of discussion, we shall consider poisonous insects 

 under these various headings. In this, as in the preceding discussion, 

 no attempt will be made to give an exhaustive list of the poisonous 

 forms. Typical instances will be selected and these will be chosen 

 largely from North American species. 



PIERCING OR BITING INSECTS POISONOUS TO MAN 



HEMIPTERA 



Several families of the true bugs include forms which, while 

 normally inoffensive, are capable of inflicting painful wounds on man. 

 In these, as in all of the Hemiptera, the mouth-parts are modified 



