72 CONNECTICUT GEOL. AND NAT. HIST. SURVEY [BuU. 



when folded ; mental setae three and a small fourth ; lateral setae 

 five. 



Thorax: femora with dark subapical rings, sometimes the tips 

 of the tibiae and tarsi faintly darker ; metathoracic wing-cases 

 extending to the middle of abdominal segment 4, sometimes to 5. 



Abdomen: with conspicuous spots on segments 1-7, two on 

 each segment, one above and one below the lateral keel ; there is 

 also a similar spot on each side of segment 8 above the lateral 

 keels ; dorsum of terga 2, 3 and 4 densely hairy, lateral keels 2-8 

 with spinules and minute setae, the spines grouped at apices of 

 2-5 and not usually more than 7 or 8 on these segments ; keel of 

 segment i without spinules or setae. 



Gills (PI. I, Fig. 8) : clear, with some transparent and some 

 black tracheae, the black tracheae frequently separated from the 

 main axis by clear stretches ; in others forming alga-like patches 

 as in exulans; tips of gills comparatively blunt, the dorsal and 

 ventral marginal spines not usually reaching beyond the middle of 

 the gills, although in one reared specimen the spines extend well 

 beyond the middle. 



Measurements : length, 12-13 "^"i- 5 length of abdomen, 8 mm. ; 

 length of gills, 4-5 mm. ; length of metathoracic wing-cases, 

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

 .5-1.5 mm. 



Adult, male. — Color blue and black. 



Head : black and blue ; antennae black except the tip of the first 

 and second segments ; postclypeus black except sometimes the 

 front margin ; front above clypeus to bases of the antennae 

 pale; remainder of the front and vertex black; postocular spots 

 large, subcuneiform, the margins irregular; occiput and post- 

 genae pale except a transverse black area behind the postocular 

 spots. 



Thorax : blue and black ; pronotum black, cephalic lobe pale, 

 median lobes with a pale spot on each lateral margin, and caudal 

 lamina also pale ; propleura black above, pale below ; dorsal meso- 

 thoracic black stripe occupying one-third to one-half of each 

 anepisternum, the lateral margins parallel ; pale stripe of the 

 anepistema extending from cephalic margin to near the wing 

 bases, widest above the katepisterna ; black stripe of the meso- 

 pleural suture widest caudad of katepisterna ; a black spot on the 

 metapleural suture cephalad of the wing bases ; remainder of the 

 pleura blue, the postcoxal areas blue or buff; legs striped black 

 and blue or buff, femora black above with a pale spot at base, 

 appearing as an emargination of the black band but obscured in 

 older specimens ; cephalic half of the dorsum of the tibiae black ; 

 tarsi and claws brown, darker at the tips of the segments ; wings 

 with 9-1 1 postnodal cross-veins in the front wing, and Mj arising 

 between the fourth and fifth of these. 



