No. 39] ODONATA OF CONNECTICUT: COENAGRIONIDAE 47 



of darker pigment occur around the margins of the g-iUs ; smaller 

 tracheae transparent and indistinct. 



Measurements: length (excluding gills), 12-17 mm.; length 

 of abdomen. 8-10 mm.; length of gills, d-'j mm.; width of gills, 

 I mm. ; length of median lobe, 2 mm. ; width of median lobe, 

 .6-1.6 mm. 



Adult, male. — Color blue, black, and yellowish orange. 



Head : black or dark brown and blue ; mouth parts yellowish ; 

 antennae black, the first segment with a blue ring; postclypeus 

 black, the anteclypeus, labrum, mandibles, their trochantins, genae 

 and the front above the clypeus to the level of the antennae, green- 

 ish blue; remainder of vertex, occiput and postgenae black. 



Thorax : black and blue, yellow on the sides ; pronotum largely 

 black, marked with blue on sides ; mesepisterna with a broad 

 dorsal stripe which is as wide as the two episterna together adjoin- 

 ing the wing bases, but contracts suddenly cephalad of this, and 

 again about half way to the cephalic margins ; katepistema black 

 and blue ; metepisterna and mesepimera blue with black caudal 

 margins, and a brownish spot on the mesepimera behind the kate- 

 pistema ; postcoxal areas yellowish buff or pollinose, the lateral 

 margins of the intersternum and sometimes the ventral marg"ins 

 of the metepimera dark ; metepimera bright yellow, legs mostly 

 black, the femora each with a broad dorsal black stripe which 

 encircles the segment at the apex ; tibiae pale buff, with darker 

 stripe on the ventral surface; tarsi black; wings with 10-13 post- 

 nodal cross-veins in the front wing; stigma usually surmounting 

 a single cell. 



Abdomen : blue and black, the first tergum with a short basal 

 black spot on the dorsum and cephalic angles ; tergum 2 with 

 broad, black dorsal stripe and apical ring; terga 3-7 black with 

 blue basal rings and pale lateral margins ; terga 8 and 9 largely 

 blue, with narrow, lateral black margins and a black mesal line on 

 dorsum of each (sometimes very faint or interrupted), the line 

 being about three-fourths the length of the segment and with two 

 small dots, one on each side of the caudal end ; terga 10 black 

 except the two small blue spots on the dorsum ; anal appendages 

 black, the superiors longer than the inferiors, swollen at their 

 apices and the mesal surfaces densely hairy; inferiors short, 

 pointed at the tips, the dorsal surface flat. Fig. 10, No. 24. 



Female. — The blue of the male is replaced by yellow or Isuff. 



Thorax : pronotum curiously modified, the caudal margins not 

 continuous, and the median lobes with a flat, curved, elevated area 

 on each ; mesostigmal plates broad, the caudal margins curved, 

 the lateral angles pointed and the caudo-lateral margins elevated. 



Abdomen : buff and black, terga 7-10 black above, the sides 

 pale; ovipositor reaching the apex of segment 10. 



Measurements : total length, male 34-35, female 33-36 mm. ; 



