2 JO Bulletin American Museum of Natural History. [Vol. XXII, 



thin and finely and verj^ regularly chagreened, except on the dorsal surface, 

 where there are six thickened sclerites, the first being very narrow, the last 

 reduced to a minute lunule, the second as long as the subequal third and fourth 

 together, the fifth narrow and with a large crescentic glandular opening in its 

 middle. There are no ventral sclerites. The seventh, eighth, and ninth seg- 

 ments are suddenly attenuated, and the last bears a pair of small foliate flaps. 

 The dorsal sclerites are covered with short uniformly distributed hairs; the 

 remainder of the abdomen, except a large patch on each side just back of the 

 hind leg and extending over about four segments, is covered with similar 

 hairs, each of which arises from a small but conspicuous, elliptical brown spot. 

 There is a circlet of macrochaetas along the posterior edge of the sixth and on 

 the anterior portion of the much smaller seventh segment. 



Legs rather stout, covered uniformly with short hairs except the coxas 

 which are nearly bare. Tips of hind coxae with a row of bristles. Tibiag with 

 prominent spiirs. Empodia fimbriated. Hind metatarsus slightly flattened 

 and bearing on its plantar surface six transverse rows of bristles. 



The body and legs are yellowish; abdomen white, except the dorsal sclerites 

 and the spots from which the hairs arise, which are dark brown. Upper surface 

 of head and thoracic dorsum light brown, the former with a dark brown, V- 

 shaped mark with its angle over the ocelli, the latter with two indistinct longi- 

 tudinal dark brown bands. 



Described from nineteen specimens taken at Utuado, Porto Rico, 

 March 17 to 19, 1906. 



This species differs from both P. liicifera and P. occidcntalis in 

 having the hind metatarsi somewhat dilated and furnished with rows 

 of bristles, and in the shape of the thorax, which is much longer than 

 in lucifcra and without the lateral sinuosities of occidcntalis. From 

 the former it differs also in the wider distribution of the stout hairs 

 on the membranous portions of the abdomen. There are also im- 

 portant peculiarities in the chastotaxy of the new species, as may 

 best be seen by comparing the figures accompanying this article with 

 those of Wandolleck and Melander and Brues. It is, perhaps, worth 

 noting that all the bristles of P. boriiiqiicnensis are bare, that is, non- 

 pubescent, just as they are in hicifcra and occidcntalis. 



Bibliography. 



Becker, Th. Die Phoriden, Abhand. zool. hot. Ges. Wicit, 1901, pp. i-ioo, 



Taf. i-v. 

 Brues, C. T. Two New Myrmecophilous Genera of Aberrant Phorid;c from 



Texas. Anter. Nalur., XXXV, 1901, pp. 337-356, 10 figs. 

 Brues, C. T. New and Little-Known Guests of the Texan Legionary Ants. 



Amcr. Natur., XXXVI, 1902, pp. 365-378, 7 figs. 

 Brues, C. T. A Monograph of the North American Phoridne. Trans. Am. 



Entom. Soc, XXIX, 1903, pp. 331-404, pU. v-ix. 

 Cook, O. F. A New Wingless Fly from Liberia. Science, VI, Dec. 20, 1898, 



p. 886. 



