Lawson: Membracid^ of Kansas. 37 



stylets. The labrum is large aiul cauchul of the elypeus, bearing the 

 more or less membranous epipharynx at its tip. All the mouth 

 parts are typical of the ordinary sucking phytophagous insect. 



The thorax, as in all insects, consists of three segments. For our 

 purposes only a brief discussion of the dorsal sclerite of the pro- 

 thorax will be necessary. This sclerite, the pronotum, as already 

 mentioned, is the chief characteristic of the family. It is one of 

 the finest examples of the biological phenomenon of orthogenesis 

 that is to be found. In our North American membracids it is com- 

 paratively simple as compared with its appearance in many Neo- 

 tropical genera, such as Sphongophorus and Cyphonia. But even in 

 our fauna it assumes such diverse forms as to give us the best 

 generic, and often also specific characters for the classification of the 

 members of this family. The following parts have been named and 

 are used in the descriptions which follow: 



1. Metopidium. The cephalic area ,of the pronotum, extending 

 from the base of the head to the front of the dorsum. 



2. Humeral angles. The angles of the pronotum just above the 

 bases of the wings. 



3. Suprahumerals. The lateral projections above the humeral 

 angles. 



4. Dorsal carina. The ridge usually extending the length of the 

 pronotum. 



5. Posterior process. The caudally directed portion of the 

 pronotum. 



The three segments of the thorax each bear a pair of legs, which 

 are composed of the usual segments, the tarsi being three-segmented. 

 The coxce are usually stout, the trochanters rather small and bent, 

 the femora large and stout, and the tibice usually long, slender and 

 hairy. In the subfamily Membracinae and in some Centrotinae, the 

 tibiae are wide and flat or foliaceous, especially so in the prothoracic 

 and mesothoracic legs. 



The last two thoracic segments each bear a pair of wings, which 

 are of value in sj^steraatic work, not only in their venation, but also 

 in their relation to the pronotum. 



The abdomen consists of eleven segments, the last two forming 

 the anal tube. Most of these segments show a distinct tergite, 

 pleurites and sternite. Of these sclerites the tergite is by far the 

 largest, forming both the dorsal and lateral portions of the seg- 

 ment; and in the case of the female ninth segment, nearly inclosing 

 the segment, coming clear down to the sides of the ovipositor, in 



