AMKIUCAN DIl'TERA. 17 



Neither am 1 t'lilly persuaded of the synunoniy of Aj>/i(ini(iif<iiiiii 

 Schiner, which oenerie iianio Prof. Brauer would adopt in preference to 

 hopogon or Leptnrf/inis to inchidc the American species of Xicocles. 

 This genus was described in 18G6 (Die Wiedemannsche AsiHden, Verh. 

 Zool. Bot. Ges. 18G6, 071) and the typical species from Venezuela, (A. 

 FraKcii/rh/il Sch.) the foUowint;- year (ibid 18()7, 372). In re<rard to 

 Dasyp. polifus Say, Schiner says (ibid 18(!7. 872): "Gehiirt in die 

 Gattung Apham<(rf((iaa, obwohl die Habitus, eine etwas abweichende 

 ist." In his generic and specific descriptions of A. Fniuettfctdii % 

 he says: '• A7)n gedrungenem Kiirperbau, kurz und plump." "Hin- 

 terleib kurz und breit, etwas eingebogen." "Genitalien des ^lannchens 

 dick kolbig, die klappen gegen die Bauch gerichtet." -'Stark verdickten 

 Hirterschenkel." Moreover he does not mention the peculiar silvery 

 appearance on the last abdominal segments, which is, I think, justly 

 entitled to generic value. In these points, the difference of which may be 

 seen by comparison of the following description, the two genera are suf- 

 ficiently separated, it seems to me, to warrant the retention of Xicoch'n. 

 for the present at least. Wherein Bldcodix diifers from Aj)/i(niiiirt<nii(i, 

 however, I am not prepared to say. I by no means affirm that these 

 genera are firmly established, but before settling their value a careful 

 comparison is needed of more species. ^Material for this I endeavor to 

 add bv the description of two aberrant forms, both of which show dif- 

 ferences that might be considered of generic value, but there have been 

 altogether too many genera made in this family already. 



27. IVicocles abdoiiiinalis n. sp. Plate I, fig?. 14. 14ii, I4ii. 



'J,. — Black, inoilerately shining, third, fourth, fifth and sixth abdominal seg- 

 ments, except the narrow lateral margins, yellowish red ; fifth segment about four 

 times broader than long. Wings variegated witli dark brown. Length 11-12 mm. 



Head much broader than high, much flattened, the face scarcely n)ore than 

 ono-fonrth the entire width, the inner margins of the eyes nearly parallel 

 throughout. Face flattened, but very slightly projecting in profile below, black, 

 somewhat shining, whitish dusted below, a row of brown bristles along the oral 

 margin, intermixed with sparse, long whitish pile, which extends upon the face 

 nearly to the antennae. Front more opaque black; the bristles on the ocellar 

 tubercle brown or blackish. Antennae black, the first two joints with blackish 

 hairs: first joint a little longer than the second, the latter short; third joint nearly 

 twice as long as the first two combined, slender, of nearly equal width throughout ; 

 style divergent, rather slender, acuminate, less than half as long as the third 

 joint, terminating in a microscopic bristle. <»ccipito-orl)ital bristles brown . jtile 

 below soft, white, rather long and abundant. Dorsum of thorax black, with two 

 broad, velvety opaque black stripes, narrowly separated by a slightly grayish 

 stripe in front, confluent behind: the rather short and weak bristles above the 

 win>^. in front of, aiul on the sciitellum, dark l)rown. Pleur.'ic thii-kly gray pubes- 



rllANS. .\MKI!. KNT. SOC. XI. (.')) ll KCr..M BKR , 1 88.". 



