Knab — On Some North American Species of Microdon. 141 



ately, makes no mention of the abdominal vestiture, but states that the 

 last two segments of the abdomen are nearly pure golden, which is hardly 

 in agreement with our specimens. 



Microdon fulgens has the hairs of the abdomen, which are very short 

 and do not obscure the body-color, for the most part black ; only at the 

 sides slight patches of pale yellow hairs can be detected. The body-color 

 varies considerably in different specimens, on the thorax from brilliant 

 metallic blue and violet to blue-green ; on the abdomen from blue-green 

 through golden green to brilliant red and nearly golden. 



Eleven specimens are before me: Okefenokee Swamp, Georgia, June, 

 1912, 2 males, 1 female (Cornell expedition); Enterprise, Florida, May 

 13, 1 female (H. G. Hubbard); Miami, Florida, October 22, 1 female 

 (C. H. T. Townsend); "Florida," 1 male, 1 female; Dade County, 

 Florida, 1 male, 1 female (E. A. Schwarz); Fort Meyers, Florida, May 

 7, 1916, 1 female (J. C. Bradley) ; Springfield, Missouri, July 16, 1912, 1 

 female (H. H. Knight). The two specimens last mentioned and the 

 three from Georgia belong to tbe Cornell collection. 



One of the males from Georgia has on the abdomen, close to the base 

 of the third segment, a velvet-black fascia; this is slightly arcuate, doubly 

 emarginate in front, and stops considerably short of the lateral margins. 

 Elongate patches of similar character appear on the lateral lobes of the 

 second segment. These velvet-black markings are not due to pubescence, 

 but apparently to a modification of the integument itself. The three 

 other males before me show medianly on the third abdominal segment 

 very faint indications of the beginning of such a fascia, but there is no 

 trace of it in the females. 



With some doubt I refer here a male from Tehuantepec, Mexico 

 (Sumichrast), and mention it only on account of the presence of the vel- 

 vety fascia of the third abdominal segment. This differs from that in 

 the specimen above described in being medianly produced posteriorly as 

 well as anteriorly. Otherwise, the only appreciable differences from 

 typical fulgens are the somewhat smaller size and less robust abdomen, 

 as well as paler wings. 



Microdon scutifer, new species. 



Female. — Moderately stout. Head black. Frons over one-third the 

 width of the head, the eye margins parallel to level of antenna? ; surface 

 rather densely covered with setigerous punctures except about ocelli and 

 above antennae; pile short, black on occiput, white in front of the obso- 

 lescent transverse furrow. Face moderately convex, narrowing very 

 slightly toward the mouth ; pubescence black in the middle, broadly yel- 

 lowish white at the sides and beneath. Proboscis bright ferruginous. 

 Antennas blackish, stout, moderately long, the first and third joints sub- 

 equal ; third joint ochreous at base, moderately stout, nearly uniform 

 throughout, bluntly rounded at apex ; arista very stout, much shorter 

 than the third joint. Mesonotum bronzy black on the disk, the humeri, 

 lateral and posterior margins broadly light ocher-yellow, posteriorly 



