82 CONNECTICUT GEOL. AND NAT. HIST. SURVEY [Bull. 



length of the gill ; basal two-fifths or one-half of the gills uniform 

 dark brown, the pigmented area followed by a broad clear band ; 

 beyond the clear portion are frequently one or two brown trans- 

 verse stripes, the apices of the gills being without pigment. 



Measurements : length, 1 1 mm. ; length of abdomen, 8 mm. ; 

 length of gills, 6 mm. ; width of gills, i mm. ; length of meta- 

 thoracic wing-cases, 3.5 mm. ; length of median lobe, 2 mm., 

 width, .5-1.3 mm. 



Adult, male. — Color pale blue and black. 



Head : blue and black ; antennae brown, the first segment some- 

 times with the cephalic half blue; postclypeus blue with a black 

 spot on each side; anteclypeus blue; labrum blue, with a black 

 dorso-mesal spot, sometimes a lateral spot on each side, the three 

 sometimes connected; front above the labrum to the median 

 ocellus blue; ocelli with small blue spots ventrad; remainder of 

 the front black; postocular spots very large, forming equilateral 

 triangles, and occupying most of the dorsal portion of the occiput ; 

 occiput and postgenae pale blue ; eyes blue in life. 



Thorax : blue and black ; pronotum with elongate blue spots 

 on the median lobe, contiguous on the meson, and somewhat cres- 

 centic spots of the same color on the sides ; proepimera and pro- 

 episterna brown or blue ; mesothorax with a black stripe covering 

 the dorsal carina frequently divided by a line of brown on the 

 carina ; black stripe of the mesopleural suture sometimes reduced 

 to a line ; mesokatepisterna with crescentic marks on the dorsal 

 borders ; remainder of the mesopleura and metapleura (except small 

 spots on interpleural folds and metapleural sutures) blue; postcoxal 

 areas pale ; legs striped pale blue or bufT and black, the coxae and 

 trochanters blue, femora blue with broad dorsal black stripes fre- 

 quently interrupted at the base by a pale spot; tibiae pale blue 

 and bufT with a short dorsal black stripe or none, the tarsi pale, 

 black at tips; wings with 10-12 postnodal cross-veins in the front 

 wings and 7-10 in the hind; M^ arising between the fourth and 

 fifth postnodal cross-veins in the front wing and between 3 and 4 

 in the hind; pterostigma small, subelliptical. and surmounting less 

 than a single cell. 



Abdomen: blue and metallic black, the dorsum of the first 

 tergum with a small black basal spot about half its length ; second 

 tergum with a black apical shield-shaped spot, the spot extending 

 to the cephalic margin and narrowed at this point to a line on the 

 meson ; terga 3-7 inclusive, with longitudinal black stripes widened 

 subapically and narrowed basally, the lateral margins of the terga 

 pale; terga 8 and 9 usually entirely blue, the eighth sometimes 

 with a dark basal spot on the dorsum ; tergum 10 black ; anal 

 appendages (Fig. 10, No. 6) short and black, the superiors longer 

 than the inferiors and appearing slightly knobbed at the apices 

 when seen in lateral profile; viewed from above, the superior 



