E. T. ORESSON, JK. 7 



and the antemiiv. Face brown, shorter than wide; sides and cheeks silvery, 

 clypeiis projecting, shininj; black. Palpi jet black. Antennse, as long as the face, 

 yellow to brown, with the third joint sometimes black ; the latter about twice as 

 long as the second and nearly as wide as long; second joint with a distinct bris- 

 tle beneath, as long as the third joint; arista black, slender, bare. Thorax 

 brownish, dusted above; pleurte more shining, with whitish bloom below; meta- 

 notum whitish poUinose. Scutellum brownish, with two erect apical bristles. 

 Halteres blackish-brown. Abdomen brown, shining; first segment the narrowest, 

 with long erect yellow hairs; posterior margins of segments 2-5 narrowly 

 whitish. The genital segments of male not enlarged ; the last segment flattened 

 laterally; the clasps are beneath the fifth segment, being two slender filiform 

 appendages on a common pedicle or base, with their anterior mesal surfaces pro- 

 vided with short black spines. The ovipositor of female is more or less awl- 

 shaped, about one-half as long, and as wide at its base as the abdomen, tapering 

 to one-half this width at the apex; the second joint filiform, more or less ex- 

 tended. Fore coxse and basal half of femora yellow; tibiie black, but tarsi snow 

 white. Middle and hind coxge, base, sometimes basal half, a preapical ring, and 

 knees of femora, yellow; apical half of tibiae more or less yellowish ; hitid meta- 

 tarsi wliite. Wings hyaline, with a broad brownish band crossing the apical half 

 of discal cell, including the posterior cross-vein ; and a brownish apical spot; first 

 posterior cell open ; anal cell acute at the apes, as long as the second basal cell ; 

 small cross-vein at middle of the discal cell. Length 8-10 mm. 



Both sexes. Pennsylvania. 



I have made drawings showing the genitalia of this .species as 

 typical for this group, but these vary in detail with each species. 

 The diiference will be readily seen at a glance, and there is no need 

 of noting them here. 



This is the common eastern North American .-species of this 

 group, and is generally found in the wood upon the bark of trees 

 and on foliage. 



Calobata fasciata Fab. 



Miiscd, Fabricius, Syst. Ent., 781, 177"). 



Calobata, Wiedmann, Auss. Zwei., ii, 53(). 1830. 

 J. — Generally rufous, rather shining. Froni, veitex and occiput rounded into 

 each other without any ridge to differentiate them; one pair of frontal bristle 

 which are opposite the ocelli; these ocelli are slightly nearer the verticals than 

 to the antennse; no post vertical bristles. Face lighter, more or less silvery. 

 Antennae shorter than the face; third joint rufous or yellow ; arista very slen- 

 der, bare. Thorax more or less pollinose, especially the lower part of the pleurte. 

 Scutellum with two diverging bristles. Halteres rufous, with darker knobs. 

 Abdomen dark brown above; segments with narrow whitish posterior margins. 

 Ovipositor shining brown, about half as long as the abdomen. Legs brown, but 

 the posterior and middle femora are more or less yellowish, excepting a brown 

 preapical ring and apex ; anterior entirely and the bases of the middle and poste- 

 rior metatarsi snow white. Wirujs hyaline, with two cross-bands and an apical 



TRANS. AM. ENT. SOC. XXXIV. .JANUARY, 1908. 



