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



Median fovea not linear and distinctly depressed below the 

 surface of the front 3 



3. Median fovea a broad, flat, indistinct depressed area, more 



distinct near the median ocellus; saw-guides strongly con- 

 vex above on the basal half and straight or slightly convex 

 below; body rufous, with a spot about the ocelli, a spot 

 near the base of wings, and the base of abdomen above, 



more or less black. Length 8 mm obsoleta 



Median fovea a distinct, narrow, elongate, diamond-shaped 

 depression, flat on the bottom; saw-guides convex above 

 on basal half and straight below; body rufous, with two 

 spots on lateral lobes of mesonotum and the postscutel- 

 lum black. Length 8 mm distincta 



4. Median fovea a wedge-shaped depression, narrowed near the 



median ocellus, with polished, sloping walls; saw-guides 

 strongly convex on basal two-thirds above and almost 

 straight below; body rufous, with antennas beyond the 

 second segment, a spot about the ocelli, a spot above the 

 base of each antenna, a spot on the apex of the median 

 lobe of the mesonotum, two spots on each lateral lobe, 

 and the two basal tergal segments black. Length 9 mm. 



ferruginea 

 Median fovea vase-shaped, a semicircular, slanting depres- 

 sion adjacent to the median ocellus, broadly boat-shaped 

 on the middle of the front, the two parts connected by a 

 narrower portion with high bounding walls; saw-guides 

 moderately convex on basal two-thirds above and straight 

 below; body rufous, with usually a spot about the ocelli, 

 and two spots on each median lobe of mesonotum black. 

 Length 8 mm inf uscata 



M. bicolor MacGillivray. 

 M. obsoleta MacGillivray. 

 M. distincta MacGillivray. 

 M. ferruginea (Say). Xyela ferruginea Say. 

 M. infuscata ( Norton). Xyela inf uscata Norton. Larva 

 feeds on the leaves of elm. 



PAMPHILIIDJE. 

 Key to Genera. 



1. Claws cleft, the two rays subequal in length; hinder margin 



of posterior orbits with a distinct fine carina 5 



Claws with a small median or submedian erect tooth 2 



