No. 34.] HEMIPTERA OF CONNECTICUT: MEMBRACIDAE. 175 



Ceresa Amyot and Serville. 



A genus usually recognized by the large size, the more or less 

 triangular shape, and the prominent suprahumeral horns of the 

 insects. The color, with two. exceptions, is green or greenish. 

 It is one of the most common and widely distributed of the genera 

 represented in the State. 



Key to Species. 



1. Brown with transverse bands 2 



Green or greenish without bands 3 



2. Large, dark-colored, tegmina strongly marked with brown; pos- 



terior process with two white bands diceros 



Small, light-colored, tegmina hyaline or only faintly clouded; pos- 

 terior process with one white band albescens 



3. Undersurface of body not strongly marked with black 4 



Undersurface of body strongly marked with black .basalis 



4. Dorsal crest marked with brown or reddish ; species small 5 



Dorsal crest concolorous 6 



5. Horns long, sharp, much recurved and elevated const'ans 



Horns short, little elevated, only slightly recurved palmeri 



6. Pronotum only sparingly pubescent or entirely smooth 7 



Pronotum densely hairy .borealis 



7. Large, 8-10 mm 8 



Small, 7-8 mm 9 



8. Horns long, sloping upward, recurved; clypeus much prolonged 



beyond vertex taurina 



Horns stout, nearly straight ; clypeus short . . bubalus 



9. Horns long, acute, slightly curved backward brevis 



Horns short, bluntly triangular brevicornis 



C. diceros (Say). (PI. iv, 9.) 



1824. Membracis diceros Say. Narr. Long's Exp., App. ii, 299. 



1835. Smilia diceros Germar. Silb. Rev., iii, 237. 



1843. Ceresa postfasciata Amyot and Serville. Hem., 540, pi. 10, fig. 3. 



1846. Ceresa diceros Fairmaire. Rev. Memb., 285, no. 11. 



1903. Ceresa vitidalis Buckton. Mon. Memb., 172, pi. 36, figs. 3~3b. 



Widely distributed. Has been recorded on a large number of 

 hosts but most commonly on black elder (Sambucus canadensis) . 

 Seems to prefer low plants. 



Recognized by its dark brown color with transverse whitish 

 bands, the stout humeral horns, decurved posterior process, and 

 infuscate tegmina. 



Field studies have indicated that its entire life history is spent 

 on one host. 



Hosts : Elder, locust, white oak, sycamore, sweet clover, black- 

 berry, butternut, boneset, goldenrod, clematis, grape, wild cherry 

 (Prunus pennsylvanicus) . 



New Haven, 19 July, 1905 (B. H. W.) ; 7 Aug., 1910 (W. E. B.) ; 

 Goshen, 6 July, 1919 (M. P. Z.) ; Branford, 29 July, 1904 (P. L. B.) ; 

 Prospect, 15 Aug., 1906 (W. E. B.) ; Litchfield, Aug. and Sept. (L. B. W.) ; 

 Portland, 24 July, 1921 (B. H. W.) ; Cornwall, 18 July, 1921 (B. H. W.). 



C. albescens VanDuzee. 



1908. Ceresa albescens Van Duzee. Bull. Buff. Soc. Nat. Sci., ix, 35. 

 Rare. In eastern New York it is most likely to be found on 



