233 



wings. In lacfcif^cnuis the win.s^s are milky white, the third vein is 

 connected with the first by means of the usual cross vein, and the 

 lower branch of the fourth vein is indistinct at its base. Both 

 species are i mm. in lcni;th and black in color, though the mesonotum 



in lactcil'ciniis is subopaciue, while in arcfica it is polished. 



MYCETOPHILID^ 



Zygonkura fenestrata, n. sp. 



Male. — Black. Frons shining; antenuc-e black, scape yellow. 

 Mesonotum shining, the hairs on the surface pale ; pleurse brown, the 

 sutures paler ; scutellum concolorous with the mesonotum. Abdomen 

 brown, subopaque. Legs brown or blackish, coxre and bases of 

 femora yellowish. Halteres yellow, knob brow^nish black. Wings 

 clear, the surface hairs giving them the appearance of being grayish; 

 veins brown. 



Ocellar region slightly raised; antennae with the second joint 

 swollen, the joints of the flagellum long-stalked, the whorls of hairs 

 long and distinct; palpi elongate, the joints subequal, slightly hairy. 

 Mesonotum with two slight longitudinal depressions, which extend 

 beyond middle and are slightly convergent posteriorly, bearing rows 

 of rather long pale hairs; the whole disc pollinose except a narrow 

 anterior central stripe and the margins of the depressions, which, 

 when view^ed from in front, gives the mesonotum the appearance of 

 being trivittate ; the pollinosity most distinct in front of the scutellum ; 

 margins of the mesonotum laterally with distinct hairs; disc of 

 scutellum and the posterior margins with long hairs. Abdomen with 

 numerous soft surface hairs, segments subequal; hypopygium large 

 and protruding, much as in Sciara (PI. XIV, Fig. 27). Legs slender; 

 basal joint of hind tarsus about two thirds as long as the tibia and 

 two and a half times as long as the second joint; tibial spurs absent; 

 claws very small. Wing as in Figure 26. 



Length, 2-3 mm. 



Female. — Similar to male except in the structure of the antenna, 

 w^hich in the male is at least as long as the entire insect and 2-14 

 jointed; whereas in the female, besides being shaped as in Figure 24, 

 the entire length of the antenna does not exceed one half that of 

 the insect, and consists of only 2-10 joints, the last joint being very 

 short. Genitalia as in Figure 23. 



Length, 2.5-3.5 rnni- 



Locality, LVbana, Illinois; a large series taken on the windows of 

 the Natural History Building of the University of Illinois during 

 November, 191 3 (C. A. Hart and J. R. Malloch). 



