INSECUTOR INSCITI.^ MENSTRUUS 69 



TWO NEW NORTH AMERICAN DIPTERA 



By R. C. shannon 



Chrysops vitripennis, new species. 



Small, black species with wings entirely clear except the 

 costal cell and the stigma. 



Female : Frons broad, at vertex about one-fourth the width 

 of head, broadening slightly toward antennae, moderately shin- 

 ing, black, with pale, short pile on posterior half and white 

 pollen along the eyes and in front before the roots of an- 

 tennae ; frontal callosity transverse, moderately convex and 

 shining. Antennae long and slender; first joint dull yellowish, 

 the apical third black ; the rest of antennae black, slightly 

 pruinose ; face rather prominent, shining black. Palpi and 

 proboscis black. Thorax and scutellum dark plumbeous, with 

 scattered short whitish pile. Abdomen concolorous with 

 thorax, with sparse short greyish pile anteriorly and longer 

 and whitish pile posteriorly. Legs black, the middle and hind 

 tarsi with the first two joints dull yellowish, black at their tips. 

 Wings hyaline, the costal cell and stigma yellowish. Squamae 

 and halteres darkened. 



Length, 5.5 mm. ; wing, 5.5 mm. 



Beltsville, Maryland, one female June 25, 1915 (R. C. Shan- 

 on) ; one female June 9, 1914 (N. Banks) ; and two females 

 June 18, 1916 (W. L. McAtee). 



Type, Cat. No. 30301, U. S. Nat. Mus. 



This species of Chrysops is the first without wing-pattern 

 to be described in this country. It is evidently rare, only a 

 few specimens having been taken. It occurs in a sphagnum 

 swamp in which there are only a few scattered pine trees. 



The patternless wings, the shining black face and almost 

 entirely black legs makes this species very distinct. Appar- 

 ently C. nigribimbo Whitney is its closest ally, but a com- 

 parison of the two shows that nigribimbo differs as follows: 

 First antennal joint all yellow, second and third joints tinged 

 with yellow ; face ferruginous and less prominent ; palpi yel- 

 lowish brown; legs more generally tinged with yellowish; the 



