AMERICAN DIPTERA. 231 



Triclis, in reference to the singular closing of the cells on the 

 hind board of the wing." 



Schiner in his Novara appends to his description of Triclis 

 ornatus the following:— "a characteristic feature of the genus 

 Triclis is also the shape of the cubital fork; the upper branch 

 is always strongly "S" shaped, and so enters the foreborder 

 of the wing as to leave a very wide opening between the two 

 branches of the fork ; in the form of the antennae there appears 

 a great variability in the different species, the third segment 

 is often long and small, in other species much shorter, and in 

 more contrasting species very short and broad. However, 

 this antennal variability is not necessary for the erection of 

 any genus-group, although it should not be overlooked." 



More recent observations have proved that the first pos- 

 terior cell of species of both Laphystia and Triclis is subject to 

 considerable variation. Dr. Williston believes that Triclis 

 should be a synonym of Laphystia, which it very closely re- 

 sembles. I am not in a position to have a definite opinion, 

 as I have but a single specimen of Triclis tagax before me, 

 and while I believe that Triclis may be a synonym of Laphystia, 

 the proportionately narrower face, with the gibbosity confined 

 to the lower portion, and the narrower and more deeply ex- 

 cavated front of this specimen, together with its more slender 

 structure, leads me to retain Triclis as a separate genus until 

 more material is at hand. 



Triclis tagax (PI. IX, fig. 3.) 



Triclis tagax Williston, Trans. Am. Ent. Soc, XI, 9; pi. I, figs. 

 6, 6a; 1883. 



$■ — Length 65. mm. — "Black, whitish pruinose; head wholly with 

 light pollen and pile; segments of abdomen with a large semicircle in 

 front and the anterior angles shining. Wings hyaline. 



Face thickly white pruinose and with white hairs in the mystax, 

 reaching nearly to the antenna;; straight on the sides, in profile gently 

 swollen below. Antennas black; first and second joints short, of nearly- 

 equal length, third small, short. Front faintly brownish; occiput 

 thickly white pruiinose on the sides; bear white. Thorax black, the 

 dorsum thickly covered with a short yellowish- white recumbent pile, 

 along the middle in front a shining stripe; bristles slender, black. 

 Pleura; thickly white pollinose, with a small shining black spot above 



TRANS. AM. ENT. SOC, XXXV. JUNE, 1909. 



