20 PROCEEDINGS OF THE NATIONAL MUSEUM. tol. 66. 



pulvilli large; third joint in middle tarsus bent. Wings hyaline; 

 posterior crossvein bent slightly inward and with a faint cloud. 

 Halteres yellow. Tegulae yellow, cilia black. 



Female. — Differs as follows from the male : Face a little more 

 ochraceous. Infra-alar cilia a little stronger. Vertex, thorax, and 

 abdomen slightly more brassy, brighter green. Red at tip of femora 

 more spread, and at base of middle and posterior tibiae more re- 

 stricted; fore tibiae yellow, with ordinary bristles; fore tarsi not 

 compressed, first joint equal to next three. Wings with faint yellow- 

 ish tinge, crossvein more oblique. 



Length, male 4.25 mm. ; female, 5.5 mm. 



Type locality. — Clementon, New Jersey, May 10, 1896, one male 

 and one female from Delaware Water Gap, New Jersey, July 8. 

 Both specimens were received from Mr. C. W. Johnson. 



Type. — In the collection of A. L. Melander. 



The type of Tachytrechus junctus Coquillett is in the United 

 States National Museum Collection as Cat. No. 13091 U.S.N.M. 



Other localities. — Hammonton, New Jersey, August 23, 1903, and 

 Lucaston, New Jersey, September 28, 1903, H. S. Harbeck, collector. 

 Lucaston, New Jersey, August 6, 1911, C. T. Greene, collector. 

 Manahawkin, New Jersey. September 5, 1905, H. S. Harbeck, collec- 

 tor. United States National Museum Collection. 



BIBLIOGRAPHY. 



1831. Stannius, F. H.— Isis von Oken, pp. 33, 261, 26S. 

 1851. Haliday, a. H.— Insecta Britannica, vol. 1, p. 173. 



1861. LoEW, H. — Monographs of North American Diptera, Part 2. Dolichopo- 

 didae, pp. 109-114. 



1877. OsTEN Sac'ken, C. R.— Western Diptera, pp. 315, 316. 



1878. MiK, .1.— Dipterologische Untersuchungen, p. 5. 



1896. Ai.DKicH, J. M. — Transactions American Entomological Society, vol. 23, 



pp. 81-84. 

 1905. Aldrich, J. M. — A catalogue of North American Diptera, Smithsonian 



Miscellaneous Collection, No. 1444. Part of volume 46, pp. 307-308. 



1909. Smith, J. B. — Annual Report of the New^ Jersey State Museum ( including 



a report of the insects of New Jersey), p. 757. 



1910. CoQUiixETT, D. W. — Proceedings of the United States National Museum, 



vol. 37, pp. 499-647. 

 1918. Van Duzee, M. C. — Entomological News, pp. 45-51, figs. 3, 4. 



EXPLANATION OF PLATE. 

 Drawings by C. T. Greene. 



Fig. 1. Tachytrechus vorax, apex of wing of male. 



2. T. rotundipennis, apex of wing of male. 



3. T. volitans, apex of wing of male. 



4. T. floridensis, apex of wing of male. 



5. T. slniulatvf<, apex of Ming of male. 



6. T. srmulatus, apex of wing of female. 



7. T. olympiae, front femur of male. 



