208 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



that the descriptiou seems to indicate is that the front and middle fe- 

 mora are more broadly yellow. The third longitudinal vein of the wing 

 is represented straight in his figure, but Macquart's figures generally 

 are unreliable. 



Tropidia mamillata. 



Tropidia mamillata Loew, Centur., i, 68. 



Habitat . — Illinois ! 



S . Length, 8'"'". Face carinate, with whitish pollen. Antennae 

 light ochraceous. Dorsum of thorax blackish bronze, shining. Pleurae 

 cinereous pollinose. Abdomen near the base black, near the tip fuscous, 

 with two interrui)ted reddish bands. Femora black, at the extreme 

 tip testaceous ; hind femora on the lower side near the base armed with 

 a strong mammiform process. Front and middle tibiae simple, reddish 

 yellow ; hind tibiae dilated, arcuate, fuscous black, base and upper side 

 reddish, the tip produced into a tooth. Tarsi reddish-yellow, fourth 

 joint black, the fifth joint in the hind pair or in all fuscous. Halteres 

 whitish. Wings cinereous hyaline ; stigma yellow. 



Translation, compared with the type. Will be very readily recog- 

 nized by the mammillate tubercle on the under and inner side of the base 

 of the hind femora; it is long and directed inwards and backwards. 



Tropidia calcarata, u. sp. 



Habitat. — Michigan ! 



? . Length, 9™™. Head black ; face and front lightly gray pollinose. 

 Antennae brownish yellow ; third joint very large, reaching nearly to 

 the oral margin, subquadrate ; arista black. Face but little produced 

 below the eyes, the lower margin of the cheeks nearly straight and 

 perpendicular to the plane of the occiput. Thorax black, but little 

 shining; humeri and pleurae pollinose. Abdomen opaque, black, or 

 dark brown, the lateral margins of the second and third segments 

 (broader in front of each) yellow; both of these segments with linear 

 hind margins ; fourth segment almost wholly light-grayish pollinose, 

 with a yellow hind margin. Legs dark-brown or black, the base of 

 tibiae, and the three basal joints of front and middle tarsi, yellow. 

 Wings brownish, clouded on outer half. 



(?. Third antennal joint smaller. The y^^How margins of the second 

 and third abdominal segments extend further inward. Hind coxae 

 with a large obtuse spur ; hind tibiae with a terminal spur. 



One male, three females, Galesburg, Michigan (Dr. Dimmock, 

 National Museum, Prof. Eiley's collection). 



The third joint of the antennae is much larger, the face shorter, the 

 dorsum of thorax apparently without the pollinose stripes, the yellow 

 markings of the abdomen less extensive, and the hind coxal spur, at 

 once distinguish this species from T. quadrata; from T. mamillata it is 

 as readily separated by the absence of the basal femoral spur. 



