ART. 15 NOTES ON ACALYPTRATE FLIES MALLOCH 31 



Structurally similar to ornata^ but there are no prescutellar ac- 

 rostichals in the type specimen. 



Length, 3 mm. 



Type.—QoX. No. 43126, U.S.N.M. From near Ledoux, N. Mex., 

 August 21 (T. D. A. Cockerell). 



DIASTATA (SPILOCHROA) PERUVIANA, new species 



Male and female. — Quite similar to ornata in general coloration, 

 but the lack of a dark mark in the costal cell of the Tying, the dif- 

 ferently marked scutellum, the tripunctate appearance of the ter- 

 gites of the apical two-thirds of the abdomen, and the rather different 

 wing markings are sufficient to distinguish the species. The abdo- 

 men is grey dusted and beyond the basal two tergites there are 

 usually three dark brown spots on each, with some miscellaneous 

 dark dots, the second tergite having the dark markings confined 

 to the apex in the form of a ragged apical fascia. The mesonotum 

 has some brownish marks on center of disk and a brown dot at 

 base of each of the larger bristles. Legs fuscous, apices of the 

 tibiae, and the tarsi, yellowish. 



Structurally similar to ornata^ but possibly presenting distinc- 

 tions in the male hypopygium which I have not dissected. 



Length, 3 mm. 



Type.—Coi. No. 43125, U.S.N.M. Female, Verrugas Canyon, 

 Lima, Peru, March 23, 1928; allotype, topotypical, June 20, 1928; 

 paratype, topotypical, June 20, 1928 (K. C. Shannon). 



Family PERISCELIDAE 



I have already given a revision of this group ^ in so far as the 

 genera are concerned and now add an additional genus, bringing 

 the total now known to five. I rather incline to hold my previous 

 opinion regarding the status of this group, as a subfamily of Sapro- 

 myzidae, but there are some characters possessed by the new genus 

 which cause me to hesitate in definitely expressing myself on the 

 point at this time and I tentatively accept Hendel's decision. 



MARBENIA, new genus 



This genus is readily distinguished from any one of the already 

 described four genera by the wing venation, the costal vein ceasing 

 at apex of third vein, and the vein at apex of anal cell being but 

 faintly indicated. In addition to these characters the face has a 

 distinct depression below bases of the antennae and three transverse 

 depressions below that, the central one of which has on each side an 

 upwardly curved bristly hair. (Fig. 9.) In my previously pubhshed 

 key to the genera in the paper above referred to I divided the group 

 into two segregates, one with the auxiliary vein without any indica- 



6Proc. U. S. Nat. Mus., vol. 68, art. 21, p. 24 (1926). 



