304 Descriptions ‘and Records of Bees. 
the third s.m. being much shorter. The mouth-parts are 
those of Diadasia, and P. tricolor, like our North American 
species of Diadasia, visits flowers of Cactacee. The vena- 
tional character holds well enough when we compare North 
American Diadasia with typical Ptilothrix, but the Brazilian 
D. murihirta, Ckll., is intermediate, having the third s.m. as 
in Piilothriz. D. sumichrasti vulpihirta, Ckll., also has a short 
submarginal. Ptilothrix agrees with the North American 
genus Hmphor, to which it is closely related, in Jacking a 
pulvillus on the feet. On this basis, as well as the short 
submarginal cell, Diadasia sumichrasti, Cresson, becomes 
Ptilothriv sumichrasti. D. murihirta, on the other hand, 
has large pulvilli, and remains in Diadasia. 
Thus the separation of Diadasia from Ptilothrizx may be 
maintained, though the genera are extremely closely allied. 
It remains to consider the status of Ancyloscelis, which 
has been often used for these insects, and ag Melitoma, 
which is preferred by Ducke. It is now considered that 
Melitoma is the prior name for Entechnia, Patton, which I 
regard as a very distinct genus. Ancyloscelis, Latr., 1825, 
included no named species, and Ancyloscelis, Spinola, 1851, 
is a synonym of Tetrapedia. In 1836, however, Haliday 
published Ancylosceles (not Ancyloscelis) for a species 
ursinus, taken by Lieut. Graves at S. Panlo, Brazil. The 
specimen is probably in the W. W. Saunders collection at 
Oxford. It was a male, 44 lines long, with the region of 
the mouth, the tegulze, and tarsi yellowish ferruginous. The - 
description might serve for the recognition of the species, 
but the generic characters are not mentioned. So far as I 
know the insect has not been collected since, and at present 
we can only say that it is probably not a Ptilothrix or 
Diadasia. In P. tricolor (Fr.) there is long hair on the 
apical half of second joint of maxillary palpus, and all along 
the side of the third, while the fourth has shorter hair at 
side. The joints of the palpus measure in microns : (1) 820, 
(2) 480, (3) 512, (4) 352, (5) 224, (6) 176. The paraglossz 
fall about 480 microns short of end of first joint of labial 
palpi. The hind spur is curved at-end. 
Diadasia australis knabiana, subsp. nu. 
?.—Labrum, mandibles, and broad apical margin of 
clypeus bright chestnut-red; legs red, the femora dusky ; 
apical bands on abdominal segments 2-4 very well defined. 
‘Tehuantepec, Oaxaca, June 380 (Ff. Knab). U.S. Nat. 
Museum. 
