142 Proceedings of the Biological Society of Washington. 



forming two deep wedge-shaped indentations into the dark color and 

 slighter ones at the transverse suture; vestiture very short and blackish 

 on the disk, yellowish white and longer on the yellow portions. Scutel- 

 lum light ocher-yellow, moderately prominent, inflated, with two rather 

 closely approximated but distinct and stout spines; vestiture rather 

 sparse, inconspicuous, yellowish gray, that on the spines whitish. Pleurae 

 ocher-yellow spotted with brown, the sternopleurae dark brown and with 

 a patch of pale golden hair. Abdomen elongate, broader than the thorax, 

 broadest at the apex of second segment, tapered very gradually to apex 

 of fourth, the fifth segment tapered to a blunt point and having the form 

 of a nearly equilateral triangle ; color dorsally ocher-yellow and blackish 

 brown, the dark color broad on the middle of the first segment and base 

 of second, continued over the third segment in a narrow median stripe, 

 on the fourth and fifth segments spreading out over most of the surface, 

 leaving only the angles broadly ochreous; vestiture of short yellowish 

 white hairs, anteriorly confined to the margins, on third and fourth seg- 

 ments tending to form interrupted posterior bands, on the fifth covering 

 nearly the entire, segment; venter ocher-yellow spotted with piceous. 

 Legs stout, piceous black including the coxae, the knees narrowly ferru- 

 ginous ; tibae densely clothed with appressed pile with yellowish white 

 silky luster; tarsi ventrally with bright ferruginous cushions ; pulvilli dull 

 ferruginous; claws large and black. Wings broad, tinted with smoky 

 gray, the veins brown; posterior angles of first posterior and discal cells 

 roundedly produced, the former with distinct appendices, the latter with 

 mere trace of stump; middle of first posterior cell with the usual spur 

 from third vein. Halteres pale yellow. Length: Body about 9 mm., 

 wings 7 mm. 



Willis, Texas, one female (J. C. Bridwell). 



Type: Cat. no. 21,417, U. S. Nat. Mus. 



This species is closely related to Microdon falcat.us Will, from the 

 Isthmus of Tehuantepec. It differs in the much larger size, wholly black 

 head, very different proportion of the antennal joints, as well as in many 

 minor details. In falcatus the third antennal joint is nearly twice as 

 long as the first, the scutellar spines are obsolete and the body vestiture 

 is black. 



Microdon remotus, new species. 



Male. — Head short, broader than the thorax, piceous black, stained 

 with dull yellow-brown about the mouth, along the sides of the face and 

 upward to transverse suture, also on occiput ; frons short, slightly over 

 one-third the width of the head, with distinct transverse suture ; ocelli on 

 a distinct callosity; vestiture dirty gray on the occiput, before transverse 

 suture yellowish white. Face moderately prominent, parallel-sided, 

 clothed with dense pile with yellow-white silky luster. Eyes bare. 

 Antennae with the first and second joints ferruginous yellow, the third 

 greatly elongated, dull black, its base and the arista ferruginous yellow ; 

 first and second joints of normal structure, the first about as long as 



