Surinam Dragon-Flies of the Agriogomphus Complex of Genera

The so-called “Agriogomphus complex” contains a number of imperfectly known little Gomphine dragon-flies which fall within the Epigomphus series of the Legion Gomphus of DE SELYS as proposed by E. B. WILLIAMSON in his paper of 1920 (Occ. Pap. Mus. Zool. Univ. Mich. 80, p. 8). The adult material hitherto recorded consists of only a dozen specimens. The group comprises four genera and the species known to us are chronologically listed below under their original names: 1. Agriogomphus sylvicola SELYS 1869, Bull. Acad. Belg. (2) 28, p. 189. 2. Cyanogomphus waltheri SELYS 1873, Bull. Acad Belg. (2) 36, p. 753. 3. Cyanogomphus demerarae SELYS 1894, Ann. Soc. Ent. Belg. 38, p. 173. 4. Cyanogomphus tumens CALVERT 1905, Biol. Centr.-Amer., Neuropt., p. 169. 5. Cyanogomphus conchinus Williamson 1916, Ent. News 27, p. 168. 6. Ischnogomphus jessei WILLIAMSON 1918, Occ. Pap. Mus. Zool. Univ. Mich. 52, p. 10. 7. Ebegomphus strumens NEEDHAM 1944, Trans. Amer. Ent. Soc. 69, p. 186. 8. Cyanogomphus uncatus FRASER 1947, Act. Zool. Lillo. 4, p. 437. It must be noted that the species mentioned under nos. 3, 4 and 5 were questionably referred to the genus Cyanogomphus. F. C. FRASER transferred Ischnogomphus jessei in 1943 to the genus Agriogomphus (Proc. Ent. Soc. Lond. B, 12, p. 162). J. G. NEEDHAM transferred Cyanogomphus conchinus in 1944 to the genus Ebegomphus (Trans. Amer. Ent. Soc. 69, p. 185). In the same paper (p. 180) he summarized the adult characters of the group. Further, he described the immature stages of three genera of the group, viz. Cyanogomphus in his paper of 1940 (Trans. Amer. Ent. Soc. 65, p. 382) and both Agriogomphus and Ebegomphus in his additional paper of 1944 (Trans. Amer. Ent. 69, p. 183, 190). In the latter paper (p. 180—181) he also characterized these stages on the basis of his knowledge of the larvae of the three genera, and concerning these characters he remarks: “These characteristics become progressively stronger in Agriogomphus, Cyanogomphus and Strumagomphus [= Ebegomphus; Strumagomphus is an error], and correspond, I think, to the specialization by reduction and readjustment seen in the wing venation of the adults”.