HOMOPTERA. 419 
Retaining therefore, as usual, the family terminations for the se- 
condary sections, and adopting Latreille’s and Burmeister’s views as 
to the division of the order into three primary sections, I propose to 
name these, in conformity with the gradation in the number of their 
tarsal joints :— 
1. Trimera. Tarsi 3-jointed; antenne minute, setigerous; wings 
areolate. (Cicada Linneus.) 
2. Dimera. Tarsi 2-jointed; antenne moderate, filiform, 5—10- 
jointed ; wings subareolate. (Aphis Zinn. and Psylla Geoffr.) 
3. Monomera. Tarsi 1-jointed; antenne 6—25-jointed; wings not 
areolate. (Coccus Linn.) 
The first section, TrimERA, corresponds with the Linnean genus 
Cicada, or the family Cicadaires of Latreille, and comprises the most 
numerous portion of the order, consisting of the largest and most 
beautiful of the species, and which have ordinarily three joints in 
the tarsi, and very small antenne, composed of three or six joints 
terminated by a slender seta; the ocelli are generally present, being 
either two or three in number; the wings are varied in their con- 
sistence in different species, but the upper pair never exhibit two 
different textures, so remarkable in the Heteroptera. The species are 
generally saltatorial ; the hind legs, however, are never disproportion- 
ately incrassated, as we have seen to be the case in other saltatcrial 
species. ‘Fhe thorax undergoes several modifications of structure ; in 
the typical species the prothorax is distinct and transverse, and the 
mesothorax, as seen above, occupies nearly the remainder of the 
thorax, being narrowed behind into a kind of scutellum, leaving the 
metathorax only visible at the sides ; on the under side the three seg- 
ments of the thorax are nearly of equal size. In Membracis, Cercopis, 
&c., the prothorax is greatly enlarged in size, and often singularly 
developed, and the mesothorax is reduced to an ordinary sized scu- 
tellum ; in all, the metathorax above is reduced to a very small size. 
The abdomen of the females is furnished with a complex instrument 
for boring into the stems of plants, in which they deposit their 
eggs. ; 
This section of the order has been especially investigated by Dr. 
Germar, who has described a very great number of species in his 
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