229 



narrowly blackened at base and apex ; mid and hind tibiai broadly- 

 blackened at bases and very narrowly at apices ; tarsal joints narrowly 

 browned at apices, the last two all brown. Wings clear ; veins yellow, 

 the cross vein and portions of the other veins adjoining it blackened. 

 Halteres yellow, sometimes slightly discolored on the knobs. Hairs 

 on body pale. 



Frons broad, about one fifth the head-width; second joint of 

 antenna globose, of moderate size, third joint about equal in length 

 to second and l)arely as long as the next two together; length of 

 antenna slightly less than the combined length of head and thorax; 

 the antennal hairs short ; proboscis about half as high as head. 

 Mesonotum with slight, irregular, backward- and outward- directed 

 furrows on the anterior lateral margins, the whole surface with rather 

 short pale hairs; scutellar hairs rather longer than those on the 

 mesonotum. Abdomen apparently partly membranous on the pale 

 portions, which causes it to contract and thus prevents one from 

 ascertaining what the normal appearance is. Legs slender, the 

 surfaces with distinct pale hairs; third and fourth tarsal joints of all 

 legs short, last joint not thickened, and with distinct central spines; 

 fore tarsi with short claws, those on the mid and hind tarsi distinctly 

 longer and subeciual in length, the inner claws slightly less robust 

 than the outer. Third vein reaching very nearly to apex of wing; 

 fourth vein forking well in front of the cross vein ; costa almost bare. 



Length, 4.5-5.5 mm. 



Originally described by Coquillett from Florida. 



Represented in the collection here by female specimens : one from 

 Algonquin, June 21, 1896 (Nason) ; one taken at electric light, 

 L^rbana, June 18, 1887; one from Salt Fork, Urbana, July 11, 1898; 

 and one reared from pupa found in the Illinois River at Havana 

 June 3, 1895 (C. A. Hart, last three). 



The above description does not agree in all particulars with that 

 gi\-en by Coquillett, but it does agree with the series of examples in 

 the National Museum collection and will serve much better to identify 

 the species than the original brief description. 



Pupa. — Length, 7 mm. Yellow, slightly shining. Thoracic 

 respiratory organs very short, about four times as long as broad, 

 slightly flattened on apical two-thirds; dorsum of thorax with several 

 raised oval areas on either side of the suture (PI. XV, Fig. 34) ; 

 length from anterior extremity to apex of wing case equal to the 

 length of the next three segments when viewed from the side; dor- 

 sal surface of segments 3 to 10 as shown in Figure 35, lateral view 

 similar to that of segment 11, shown in Figure 36; apical segment 

 bifid (Fig. 37). 



