448 Mr. T. D. A. Cockerell on 
is extremely similar to JZ. humilior, but differs in having the 
hair on the inner side of the basal joint of the hind tarsi 
black or almost so. Both this insect and humilior have the 
two apical segments of the abdomen clothed with sooty hairs, 
whereas Cresson says that the hair on these segments in 
intermedia is pale. In both the New Mexico insects, alse, 
the apical plate is triangular and bluntly pointed, I think 
not so broadly rounded as it should be in intermedia. These 
bees have an extremely close resemblance to certain species 
of Synhalonia, but their mouth-parts are those of Melissodes. 
The maxillary palpi of MMelissodes are always said to be 
4-jointed; but as a matter of fact the fourth joint usually 
bears a distinct rounded or cylindrical apical papilla, from 
which grows a single stout bristle; this papilla is evidently 
the rudimentary fifth joint. In MJ. humilior the papilla is 
unusually long, so that it really looks like a sort of small 
fifth joint; but the fourth joint broadens towards its base, 
and is not differentiated by a distinct suture from the third, 
which is quite stout. In J. intermedia (v. e. the New Mexico 
insect so named) the third joint is narrower, and is separated 
by a very distinct suture from the fourth, which is not 
at all broadened basally ; the apical papilla is minute and 
inconspicuous. 
No doubt Synhalonta is a more primitive type than 
Melissodes, but between the two stands Nenoglecca with 
distinctly 5-jointed maxillary palpi. ‘The fourth joint in 
Xenoglossodes is much larger than the fifth, which would 
only need to be moderately reduced to reach the exact con- 
dition found in some Melissodes. Thus we have evidence 
of the gradual reduction of the fifth joint; it by no means 
disappeared suddenly by De Vriesian mutation ! 
I will now describe a species which has the palpi of 
Xenoglossodes, but altogether the external appearance of 
Melissodes or Synhalonia ; in fact, it is so like MZ. humilior 
that at first sight I took it to be the same. It cannot go in 
Florilegus, which also has 5-jointed maxillary palpi, as the 
joints are not moniliform, and the general appearance of 
the bee is not at all the same. 
Xenoglossodes excurrens, sp. 0. 
9 .—Length about 10 millim. 
Broad, similar to Melissodes humilior, but antenne a trifle 
longer, the last joint longer than the penultimate (in humelior 
they areequal); pubescence of thoracic dorsum pale ochraceous, 
without any black ; hair on inner side of basal joint of hind 
