332 COSTA RICAN EPIGOMPHUS (oDONATA) 



Key to the Females of Costa Rican Epigomphus 



I. One pale green or yellow antehumeral stripe and a more posterior pale 



green or yellow antehumeral spot, the latter representing the upper 

 end of the second antehumeral stripe of §11. 

 Behind each lateral ocellus no tubercle projecting markedly above the 

 level of the ocellus itself. 

 Vertex without five longitudinal grooves, occiput without a strong 

 postero-superior tubercle at each lateral extremity. 

 In dorsal view each lateral ocellus subequally distant from the mid- 

 dorsal line of the head and from the adjacent eye-margin. 



subsitailis, new species 

 In dorsal view each lateral ocellus two to four times as far from the 

 mid-dorsal line of the head as from the adjacent eye-margin. 



quadrsacies 

 Vertex with five longitudinal grooves, one median, two lateral ocellar 

 and two parocular; occiput with a strong posterior or postero- 

 superior tubercle, or rounded horn, at each lateral extremity. 



tumefactus 



Behind each lateral ocellus a stout tubercle projecting much above the 



level of the ocellus itself. (Differs from arrna'us also in having no 



such deep pits on the rear of the head. Cf. figs. 25, 26, 29, 30, j)l. 



XV,) verticicornis 



II. Two narrow pale green or yellow antehumeral stripes, the posterior 



one close to the humeral suture. 

 Behind each lateral ocellus no tubercle projecting dorsad markedly above 



the level of the ocellus itself subobtusus 



Behind each lateral ocellus a stout tubercle which projects dorsad mark- 

 edly above the level of the ocellus itself. Rear of the head with a 

 much deeper pit each side than in the preceding species. 



armatus 



The female of E. comelus is still unknown. 



The structure of the head of the females is described under the 

 section of this paper entitled "Mutual Mating Adaptations," 

 pages 338-352. It is, therefore, omitted from the following 

 notes on some of the species. 



Epigomphus camelus 



Epicfomphus camelus Calvert, Biol. Cent-Amer., Xeur., pp. 170, 172, tab. 



viii. figs. 1-3 (apps. cf ), 1905. 



The following is based on the three males listed anlea, page 325. 



cf . Pale color (blue?) on the dorsal surface of the frons separated into two 

 spots, right and left, by a narrow median blackish stripe. 



Metepimeron with a dark brown stripe along its ventral margin, parallel 

 to the brown stripe on the second lateral suture and at mid-length wider 

 than the pale yellow which separates it therefrom. 



