Kinsey: The Genus Neuroterus 
27 
The structures most typical of the insects of this genus 
are the furrow at the base of the scutellum, there being no 
fovese, the absence of a suture separating the scutellum from 
the mesonotum, and the relatively smooth mesonotum with- 
out lines or grooves (traceable in 3 of the smallest subgenera) . 
It should be remembered that the males, in specific and vari- 
etal characters, are more distinctive than the females. 
The following key is based on all of the sorts of data 
available for the taxonomic treatment of Neuroterus, and is 
in accord with our knowledge of the phylogeny of the species. 
A fuller picture of the phylogeny is given in figure 1 ; and 
the best linear arrangement of the American species may be 
taken from the key. For convenience of reference, the order- 
ing of the detailed descriptions of subgenera, species, and 
varieties in the body of the paper is alphabetic within each 
group. 
1. With practically no traces of parapsidal grooves; tarsal 
claws very fine, simple (very weakly toothed in con- 
tortus) ; ventral spine very short; areolet placed sym- 
metrically below the apex; length 0. 6-2.2 mm. 2 
With traces of parapsidal grooves; tarsal claws of more 
moderate weight, simple or toothed; ventral spine more 
evident ; areolet extending mostly to one side of the apex ; 
length 1. 5-3.0 mm. 3 
2. Malar furrow quite evident; antennse with 13 segments; 
length 0.6-1. 5 mm.; male colored largely as the female, 
the eyes hardly enlarged, the third antennal segment not 
enlarged nor curved; thorax not more elongate; gall 
inseparable or separable, polythalamous or monothala- 
mous; North America; alternating galls nearly identical; 
generations bisexual and agamic, or both of one type. 
Subgenus Diplobius, 5 
Malar furrow almost or entirely lacking; antennse with 
14 segments; length 1. 0-2.2 mm.; male colored largely 
as in the female, the eyes much enlarged, the third anten- 
nal segment not longer but curved; galls simple, poly- 
thalamous, or single cells; exclusively Old World species. 
Subgenus Neuroterus 
Malar furrow quite evident; antennse with 13 segments 
(14 in duhius) ; length 1.2-2.2 mm.; male usually with 
