﻿544 HEMIITERA 



more or less modified for the reception of the tibia when closed on it : mostly- 

 aquatic forms. 2. Pagiopoda. 



Division 1. Tkochalopoda. 



This division includes the majority of the families of Heteroptera — viz. 

 the whole of the terrestrial families except Saldidae and the Acanthiae of 

 Schiodte, and it also includes Nepidae, a family of water-bugs. 



Division 2. Pagiopoda. 

 This includes the six purely aquatic families of Heteroptera, except 

 Nepidae, which appear to have very little connection with the other aquatic 

 bugs. The only terrestrial Insects included are the Saldidae and the 

 Acanthiae ; in these the femora are not modified as they are in the aquatic 

 forms. Hemiptera that live on the surface of water, not in the water, are 

 classed with the terrestrial species. With these exceptions this arrange- 

 ment agrees with that of Gymnocerata and Cryptocerata as usually 

 adopted, 1 and therefore followed in the following pages. Schiodte's 

 characters, moreover, do not divide his two divisions at all sharply. 



Sub-Order II. Homoptera. 

 Tarsi usually three-jointed . . Series Trimera. 



„ ,, two-jointed . . ,, Dimera. 



„ „ of one joint , . ,, Monomera. 



The classification of Homoptera is in a most unsatisfactory' state ; 2 . no two 

 authors are agreed as to the families to be adopted in the series Trimera. 

 We have recognised only five — viz. Cicadidae, Fulgoridae, Membracidae, 

 Cercopidae, and Jassidae. The Dimera consists of Psyllidae, Aphidae, 

 Aleurodidae ; and the Monomera of Coceidae only. It is usual to associate the 

 Dimera and Monomera together under the name of either Phytophthires or 

 Sternorhyncha, but no satisfactory definition can be given of these larger 

 groups, though it seems probable that the families of which they are com- 

 posed are natural and distinct. 



Sub-Order I. Heteroptera. 



Series 1. Gymnocerata. 



The majority of the terrestrial families of Heteroptera form 

 the series Gymnocerata, in which the antennae are conspicuous, 

 and can he moved about freely in front of the head, while in 



1 A table of the families is given by Ashmead, but docs not work out quite 

 satisfactorily, Entom. Americana, iv. 1888, p. 65; a brief tabic of the characters 

 of the British families is given by .Saunders, Hemiptera-Heteroptera of the British 

 Islands, 1892, p. 12. 



- Those who wish to see tables of the families arc referred to Ashmead, loc. 

 cit. ; to Pascoe, Ann. Nat. Hist. (5) ix. 1882, p. 424; to Stal's Hemiptera Afn- 

 cana, vol. iv. 1866 ; and for the families found in Britain to Edwards, Hevniptera- 

 Homoptera of the British Islands. For a discussion in Danish on the value of the 

 characters used, cf. Hansen, Ent. Tidskr. xi. 1890, pp. 19-76. 



