HOMOPTERA. 53 



not absolutely follow it, and points out again that the Dimera 

 consist of Psyllidae, Aphidae, and Aleurodidae, and the Monomera 

 of Coccidae only. These last two divisions are usually grouped 

 together under the names of either Phytop7it7iir-es ov Sternorhyncha, 

 and the first, with which we now only deal, may be still known 

 as Trimera*, or, as written by others, the " Auchenorrhynchous 

 Homoptera," 



The division of this section of the Homoptera into families has 

 produced much diversity of opinion among entomologists, and it 

 seems necessary to repeat that as these Ehynchotal volumes are 

 faunistic and not taxonomical in their aim, it is vninecesary to 

 enter into a purely classificatory discussion. 



Westwood recognized only three families, Cicadida?, Fulgoridse, 

 and Cercopidfe. Stal's division included four, Sti'idulantea, Cer- 

 copida, Jassida (including Membracida), and Fulgorida, in which 

 view he is supported by so good an authority as Hansen. Most 

 modern writers consider the Membracidse a distinct family, and 

 thus recognize five families in all, a course with w-hich I fall in 

 line. It may be mentioned that Pascoe (A. M. N. H. [5] ix. 

 p. 442) proposes thirteen families; and Edwards (Hem. Horn. 

 Brit. Islds.), excluding Psi/Uina, enumerates fifteen. 



Hansen (Eatomol. Tidskr. 1890, p. 19) has written an excellent 

 memoir on the four families he recognizes as belonging to this 

 section, founded on considerations drawn principally from the 

 structure of the antennae and legs and from the position of the 

 spiracles. As much of this valuable informa*:ion is based on 

 minute and microscopical investigation I have added his observa- 

 tions to the descriptions of the different families, and for the 

 synopsis relied more largely on Stal, who was again the pioneer 

 in this field, and whose work enabled the Homoptera to be 

 adequately understood. In treating the Membracidae as a distinct 

 family, I, in common with other authorities, differ from the views 

 of Stal and Hansen, though possibly on morphological grounds 

 these authors may be quite right in relegating the Membracids to 

 a subfamily of the Jassidae. 



Si/nojjsis of the Families of the Homoptera. 



A. Ocelli three, placed on disk of vertex. 



a. Antennae composed of a short basal joint, sur- 



mounted by a hair-like process divided into 

 about five joints ; anterior femora incrassated 

 and generally spinose beneath ; abdomen in 

 males with a sonorous apparatus on each side of 

 base Cicadidae. 



B. Ocelli two (rarely three or entirely absent). 



b. Ocelli placed beneath or near the eyes, usually 



in the cavities of the cheeks. 



* This is a not perfectly constant character, as in some Cicadas the tarsal 

 joints are only two. 



