INSESSORES. 



185 



Hab. — Upolu, Samoan Islands. Specimen in Nat. Mus. Wash- 

 ington City. 



The species of the genus of swallows to which this bird belongs, 

 would be sufficiently difficult to distinguish, with all the appliances 

 and means at hand, but with the brief descriptions of naturalists, and 

 no figures worth mentioning, the case very nearly borders on the im- 

 possible. And so, after having in vain examined all authorities within 

 our reach, we are constrained to admit that we find ourselves at a loss 

 to say whether the bird now before us has been previously described 

 or not. In our catalogue of swallows, in the collection of the Academy 

 of Natural Sciences of Philadelphia (Proceedings, VI, July 1st, 1853), 

 we cited Mr. Peale's name as a synonym for CoUocalia francica (Gm.), 

 relying on the evident similarity of the Expedition's specimens with 

 the description by Gmelin, and on European labels to specimens of a 

 very similar if not identical species in the collection of the Academy. 

 The latter bear as their locality " Mauritius." Gmelin compiles from 

 Buffon (Hist. Nat. des Ois. VI, p. 69G), who gives the same locality, 

 (Isle of France). The specimens in the collection of the Expedition 

 are from the Samoan and the Feejee Islands, and are only rather 

 darker in color than those to which we allude above. This character, 

 however, and the widely different locality, have mainly induced us 

 provisionally to regard the present bird as a distinct species. 



Mr. Peale's observations on this species are in a high degree inte- 

 resting: 



" When the Expedition visited the Island of Upolu, in the month 

 of November, 1839, Mr. Cunningham, acting British Vice-Consul, in- 

 formed us that he had discovered in a cave on the south side of that 

 island, some curious swallows, which had never been seen elsewhere, 

 and that they were entirely subterranean, hatching their eggs and 

 feeding and raising their young in the dark recesses of the earth. 



" We had previously seen both fishes and reptiles taken in such 

 situations, but were not prepared to hear of subterranean birds. A 

 journey was therefore made to the cave described by Mr. Cunningham. 

 It rained the whole time, which was four days, occupied in going and 

 returning across the mountains, but having become accustomed to 

 marching in mud and water, we enjoyed the tramp, and picked up, 

 besides swallows, many interesting objects, which we saw in numbers 

 every day that we stayed on the island. 



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