202 AN INTRODUCTION TO ENTOMOLOGY. 



known genera, including hundreds of species. Less than a score of 

 species are now catalogued from the United States ; but- doubtless 

 many more will be found. 



There are two well-marked sub-families. 



Sub-family I. — Tingitin^e. 



This division includes nearly all of the known species. Here the 

 scutellum is usually covered by an angular projection of the pro- 

 notum ; and the wing-covers have no distinction between the clavus, 

 corium, and membrane. 



The genera that occur in the United States can be separated by 

 the following table :* 



A. Discoidal and costal areas of hemelytra rarely jointly elevated ; when so 

 elevated, the lateral margins of pronotum never broadly foliaceous, nor with 

 the narrow foliaceous parts (when they are present) produced cephalad. 

 B. Rostral sulcus of the sternum not interrupted by a transverse ridge (be- 

 tween the mesosternum and metasternum). 



C. Costal area of hemelytra furnished with a regular single or double 

 series of areoles. 



D. Costal area with a single series of areoles. i. Teleonemia. 



DD. Costal area with a double series of areoles. 2. TlNGIS. 



CC. Costal area of hemelytra, at least in part, furnished with a triple or 

 multiple, sometimes confused, series of areoles. 

 D. Joint 1 of antennae not twice as long as joint 2. 



E. Pronotum with a single longitudinal mesal ridge (carina) ; third 



joint of antennae not at all slender. 3. Leptoypha. 



EE. Presternum with three parallel longitudinal ridges (carinae) ; third 



joint of antennas slender. 4. Physatochila. 



DD. Joint 1 of antennae at least twice as long as joint 2. 



E. Oblong, anal margins of hemelytra somewhat concave. 



5. Leptostyla. 



EE. Oval, anal margins of hemelytra convex. 8. Acalypta. 



BB. Rostral sulcus of the sternum interrupted between the mesosternum 



and metasternum by a transverse ridge. 6. Gargaphia. 



AA. Discoidal and costal areas of hemelytra jointly elevated ; lateral margins 



of pronotum broadly foliaceous, produced cephalad. 7. Corythuca. 



The following species will serve as an illustration of this sub- 

 family. 



The Hawthorn Tingis, Corythuca arcudta. — This I found very 

 abundant in Washington, puncturing the under surface of the leaves 



* Prepared by Professor H. E. Summers. 



