28 



Poisonous Arthropods 



Setat 



Sheath,* la.biu.rn 

 Mandible cutd MaxiJloe, 



Beak of hemipteron. 



to form an organ for piercing and 

 sucking. This is well shown by the 

 accompanying illustration (fig. 16). 

 The upper lip, or labrum, is much 

 reduced and immovable, the lower 

 lip, or labium, is elongated to form 

 a jointed sheath, within which the 

 lance-like mandibles and maxillae 

 are enclosed. The mandibles are 

 more or less deeply serrate, depend- 

 ing on the species concerned. 

 The poison is elaborated by the salivary glands, excepting, possi- 

 bly, in Belostoma where Locy is inclined to believe that it is secreted 

 by the maxillary 'glands. The salivary glands 

 of the Hemiptera have been the subject of 

 much study but the most recent, comprehen- 

 sivejwork has been done by Bugnion and Popoff , 

 (1908 and 1910) to whose text the reader is 

 referred for details. 



The Hemiptera have two 

 pairs of salivary glands : the 

 primary gland, of which the 

 efferent duct leads to the 

 salivary syringe, and the 

 accessory gland, of which the 

 very long and flexuous duct 

 empties into the primary duct 

 at its point of insertion. 

 Thus, when one observes the 

 isolated primary gland it appears as though it 

 had efferent ducts inserted at the same point. In 

 Nepa and the Fulgorida there are two accessory 

 glands and therefore apparently three ducts 

 at the same point on the primary gland. The 

 ensemble differs greatly in appearance in different 

 species but we shall show here Bugnion and 

 PopofFs figure of the apparatus of Notonecta 

 mawtota, a species capable of inflicting a painful 

 bite on man (fig. 17). 



-Cfferent canal 

 from pump 



Sal I* or </ pump 



17. 



Salivary glands of 

 Notonecta rnaculata. 

 After Bugnion and 

 Popoff. 



18 ' s P aHv7^ g p^p r oTFui 



