146 Annals of the Carnegie Museum. 



impura and tinctipennis , but the " notable differences " between the two 

 females do not appear from his description, as the dimensions given 

 for them are exactly alike (abdomen 23, hind wing 19 mm.), and the 

 number of postnodals (postcubitals) for the male of tinctipennis is not 

 stated. From the data which are given above for tinctipennis, it seems 

 possible that de Selys' impura female may also be tinctipennis. 



58. Argia chapadae sp. no v. 



(Plate IV, figs. 76, 76^.) 



d\ Rear of the head black, with a narrow pale stripe along each eye, 

 margin. Black of the frons not reaching as far down as the level of 

 the first joint of the antennae, which joint is blue anteriorly \ fronto- 

 nasal suture with a black line. Pale (blue) antehumeral stripe widen- 

 ing from above downward, at mid-height one-half to two-fifths as wide 

 as the black mid-dorsal. Black humeral stripe widened at both ends, 

 at the lower end as wide, at mid-height three-fourths as wide, as the 

 pale antehumeral, forked in its upper fourth or two-fifths, both branches 

 reaching to the upper margin of the sclerite, the mesepimeral branch 

 noticeably curving backward (caudad) to attain also the upper end of 

 the obsolete first lateral thoracic suture. A narrow black stripe on the 

 entire length of the second lateral thoracic suture or obsolete on the 

 lower half thereof. Abdominal segment 2 blue, a black stripe on each 

 side from end to end of the segment, curving mesad just in front of 

 its hind end toward, but not meeting, its fellow of the opposite side 

 on the dorsum; side below this stripe blue, unmarked; the dorsal 

 blue of the anterior part of the segment two-thirds to four fifths as wide 

 as the segment itself; 3-6 predominantly blue in dorsal view, each 

 with a longitudinal black stripe on each side beginning just behind the 

 usual transverse basal blue ring and widening to meet its fellow of the 

 opposite side on the dorsum in the hindmost fifth or sixth of each 

 segment (or in some the fourth of 6) ; 7 black with a narrow trans- 

 verse basal blue ring, mid-dorsally interrupted with black ; inferior 

 lateral margins of 3-7 blue, except in the hindmost sixth of each seg- 

 ment ; 8-10 blue, with an inferior black stripe on each side as long as 

 the segments. 



$. A single female seems to belong to this species. It differs from 

 the male as follows : Nasus black, a small pale spot on each side, black 

 of the frons reaching down between the antennae to the level of their 

 bases (first antennal joint remaining pale anteriorly) and connected 



