Kinsey: The Genus Neuroterus 
7 
relationships. Again it is easier to catalog or to express 
relationships than it is to catalog and express relationships 
at once. The two functions are often intrinsically incompat- 
ible. The present arrangement is very evidently neither the 
best cataloging nor the fullest expression of the phylogeny, 
but is rather an attempt to reconcile the two. The Dalla 
Torre and Kieffer 1910 arrangement of Neuroterus species 
(Das Tierreich, XXIV, pp. 307-342) divides the Old World 
species from those of America, thereby effecting some more 
or less natural grouping. The Old World species of the 
subgenus Spathegaster are more or less accidentally grouped 
together because their life histories are known ; the rest of 
the treatment is a tabular arrangement of all the published 
names, which ordering makes a good catalog only for a small 
group, and gives no information as to relationships. The 
Beutenmuller 1910 monograph of the American species (Bull. 
Amer. Mus. Nat. Hist., XXVIII, pp. 117-136) is wholly a 
tabular arrangement except that the adjacent positions of 
species with similar galls results in some cases in a correct 
expression of relationships. The chief criticism of the clas- 
sification in that paper is its inconsistency in dealing with 
closely related but distinct things; some of those forms are 
treated as separate species (e.g. hatatus and noxiosus; niger 
and papillosus; vernus, hdssettii, exiguus, and distortus; etc.), 
while others which are fully as distinct are buried in syn- 
onomy (e.g. exiguissimus, p er minimus) . As long as no cat- 
egories but genera and species are recognized in a classifica- 
tion, it will always be difficult to show the several degrees 
of relationships which actually exist in nature. For that 
reason I have employed subgenera and varieties in addition 
to species and genera, and altho there is often need of still 
further categories to show the actual degree of relationships, 
further subdivision would probably destroy the convenience 
of the catalog and the nomenclature. Fortunately we may 
often omit the use of the subgeneric name, and we may employ 
either the varietal or specific name as the needs of the occa- 
sion may warrant. 
It is debatable what may be the number of the subgenera 
worth recognizing in the genus. The described species cer- 
tainly belong to fourteen groups, but altho such an arrange- 
ment would best express relationships, it would be of little 
