110 Psyche [March-June 
it is worth repeating that, as delimited by Mann, the subgenus 
Rhachiocrema contained only two species, wheeleri and para- 
doxa. Other features connected with Mann’s characterization 
of Rhachiocrema were by no means so clear. The antennae were 
said to be elongate, twelve-jointed and with a distinct two-jointed 
club. The first and last of these characters would not, of them- 
selves, confer distinction since several species in the subgenus 
Orthocrema have elongate antennae with two-jointed clubs. But 
the number of antennal joints, as given, is unique for Cremato- 
gaster. All other known species have eleven-jointed antennae 
or, in the case of the subgenus Decacrema, ten- or nine-jointed 
antennae. If Rhachiocrema possessed twelve- jointed antennae 
its status could be defended without reference to any other 
structure. Unfortunately this is not the case. Mann overlooked 
the fact that Emery had described paradoxa as having eleven- 
jointed antennae, and he miscounted the antennal joints of 
wheeleri. Both species have eleven-jointed antennae and Mann’s 
description and figure of wheeleri cannot be relied upon in this 
particular. When Wheeler published a key to the subgenera of 
Crematogaster in 1922 (3) he included Rhachiocrema with that 
group of subgenera which have eleven-jointed antennae. Al- 
though no comment was made concerning the correction it may 
be presumed that it was based upon an examination of type 
specimens of wheeleri. To make certain that there is no further 
confusion in this matter I requested Prof. F. M. Carpenter to 
examine the type material of wheeleri in the collection of the 
Museum of Comparative Zoology. Prof. Carpenter has very 
kindly done so and informs me that specimens have antennae of 
eleven joints. While this fact does not necessarily invalidate 
the status of Rhachiocrema it does place a different value on 
the other diagnostic characters. 
Mann’s description of Rhachiocrema appeared after the 
Myrmicine section of the Genera Insectorum (4) had gone to 
press. In the preface to that section Emery stated that it was 
limited to species described up to the end of 1918, but he made 
an exception in the case of wheeleri. This species was not listed 
in the usual way but referred to in a footnote on the u paradoxa 
group,” a cluster of four species which Emery included in the 
subgenus Orthocrema. This footnote contained a peculiar 
anachronism. Although it correctly cited wheeleri as the type 
of Rhachiocrema and gave accurate reference to Mann’s publi- 
