234 Prof. J. C. Schiódte on the Morphology 
under water, and have short antenns hidden under the 
cheeks; their spiracles are by special contrivances secured 
against the entrance of the water; and the last pair is trans- 
formed into a long respiratory tube. 
The triangular posterior coxe of the pagiopodous Hetero- 
ptera join the metathorax with the whole of their open base, 
and occupy its posterior margin; they reach, consequently, as 
far out to the sides as the metathorax, but a part of their real 
extent is sometimes hidden by the margin of the metathorax 
forming a flat projection which covers their external part, 
basis of the abdomen is naked. Recent authors, not being 
aware of the important character which binds them together, 
have split them into a great number of small families, and 
mixed them up with Trochalopoda. According to the localities 
in which they live, they are divided into :—Acanthie (Capsus 
and Miris, Anthocoris, &e., and Xylocoris, Salda, Leptopus), 
with free antennz; Pelegoni, living on shores, with hidden 
