Occasional Papers of the Museum of Zoology 3 



Desmogomphus, compared with its allies, is a relatively slender 

 gomphine and the legs are weaker and slightly longer than in 

 related genera (Progomphus and Gomphoides; I do not know 

 D iaphlebia) . Type of genus, Desmogomphus tigrivensis, new species. 



Desmogomphus tigrivensis, new species 



Abdomen, male 30 . 5 ; hind wing, male 24. 



Male. — Rear of head dull brown, darker about the foramen and 

 lighter below, where it is indefinitely patterned with dull yellow; 

 genae, face, and frons above bluish gray or lead-colored, obscurely 

 and indefinitely patterned with brown as follows: labrum with 

 the anterior edge (dark brown, almost black) and a median 

 posterior spot, rhinarium and nasus with more or less diffuse 

 central areas, and frons in front, excepting the angle, and above 

 at the base in the median Une. Angle of frons low and rounded. 

 Vertex and occiput dark brown or black; anterior face of vertex 

 relatively flat, in a plane about parallel to the nasus, smooth and 

 bare; dorsal surface with a low median longitudinal sulcus, 

 punctate and bearing hairs equal in length to those on the occipi- 

 tal border, the lateral margins of the middle lobe of the prothorax, 

 and the mesothoracic transverse carina; occipital border broadly 

 concave. 



Prothorax brown; anterior lobe largely dull yellow, especially 

 above and in front; middle lobe with a median posterior geminate 

 bluish-gray spot and one or two yellow areas on each side below; 

 hind lobe with yellow shadings on the posterior border. 



Thorax rich dark brown marked with olive green. Beneath 

 pale yellowish brown. 



Abdomen relatively slender, dark brown basally, progressively 

 darker apically till the apical segments, beginning at the fourth or 

 fifth, are black; marked with yellowish or greenish as follows: 

 segment i largely pale, the dorsal apical half or slightly less, brown; 



