104 INSECUTOR INSCITI^ MENSTRUUS 



The present arrangement is new, replacing that of the former 

 table (Ins. Ins. Mens., vi, 75, 1918), although based on the 

 same principle. I give the groups the names of the oldest 

 American species. The north European species belong to the 

 same groups, and their names will generally be older than ours, 

 so that when the faunae are combined, these will prevail ; but 

 I have not yet had the opportunity to compare that fauna ex- 

 haustively, besides which the synonymy of the European forms 

 has not been settled on the present basis of specific sub- 

 division. 



Table of Groups of Heteronycha 



1. Basal lobes modified, obsolete as such, but leaving a large spine 



on one side and two approximate setae on the other, the 



latter sometimes obsolete Group puUattis 



Basal lobes more or less developed 2 



2. Basal lobe elongate, semidetached, the setiferous part sepa- 



rated from the spine Group serratus 



Basal lobe sessile, the setae not apart from the spine, or spine 



wanting 3 



3. Basal lobe more or less expanded and tubercular, with or with- 



out a spine 4 



Basal lobe uniformly long-haired ; no spine 8 



4. Basal lobe expanded, with many setae, but without a single 



differentiated long spine ; if the marginal spines are 



thickened, more than one is involved Group curriei 



Basal lobe with a single differentiated spine, or if absent, the 



lobe is flat and rugose 5 



5. Apical lobe with short, flat, clinging setae Group punctor 



Apical lobe with the setae normal, or slightly thickened 6 



6. Setae on apical lobe more or less well-developed ; filament of 



claspette without retrose spine 7 



Setae on apical lobe practically absent ; filament of claspette 



with retrose spine Group scapularis 



7. Setae on apical lobe more or less distinctly outwardly directed 



when the lobe is retracted, not functioning as organs of 



prehension, tending to obsolescence Group impiger^ 



Setae on apical lobe inwardly directed, often distinctly func- 

 tional, though occasionally obsolescent Group stimulans 



* Using impigcr in the sense of decticus. 



