Vol. XXVli] ENTOMOLOGICAL NEWS. 167 



A new Cyanogomphus (Odonata). 

 By E. B. WILLIAMSON, Bluffton, Indiana. 



(Plates VIII, IX) 



Three specimens of Cyanogomphus have been recorded. 

 Each is the type of a new species. The genus was established 

 by de Selys in 1873 (Trois. Add. Syn. Gomph.) for the new 

 species ivalthcri, known from a single male from Rio Janeiro, 

 Brazil. Its relationships with Epigomphus and Agriogowphus 

 were discussed and analyzed for several characters. Perhaps 

 the most striking single character of C. waltheri is the remark- 

 able shape of the tenth abdominal segment where the lower 

 posterior border is cut out with the resulting peculiar relative 

 positions of the bases of the superior and inferior appendages. 



The second specimen was described by de Selys (Ann. Soc. 

 Ent. Belg. xxxviii, 1894) as C. ? demcrarae. This specimen 

 was from Demerara, British Guiana, and unfortunately lacked 

 the last four abdominal segments. (The text is confusing on 

 the extent of the injury ; at one place it is stated 7 segments 13 

 mm.; at another the 5th-ioth segments lacking; in the text 6 

 segments are described.) The anal triangle is 2-celled, and 

 brief mention is made of the accessory genitalia. It is much 

 smaller than C. waltheri and de Selys remarks, "C'est une des 

 plus petites Gomphines connues," adding that it will be neces- 

 sary to know the abdominal appendages before deciding cer- 

 tainly that it belongs to the genus Cyanogomphus. 



The third specimen is a female from Atoyac in Vera Cruz, 

 Mexico, described by Calvert (B. C. A.) as C? lumens. The 

 specific name refers to a peculiar swelling on the rear of the 

 head above, behind the eyes "the swollen portions continuous 

 with the occiput and extending outward and downward along 

 each posterior eye margin to about the level of the upper sur- 

 face of the frons ; when the head is viewed from the side the 

 point where the swelling ceases inferiorly is seen to coincide 

 with a posteriorly directed obtuse angulation of the posterior 

 eye margin." This character is not mentioned for de Selys' 

 two species, though I believe it probably exists in both. In 



