148 
Psyche 
[September 
such problems as the ancestral zone and factors responsible for shift 
will arise however from integration of pro-and pterothoracic varia- 
tion. Limited evidence suggests that the predominant direction of 
shift, in extant forms, has been from substrate to surface, coincident 
with the evolution of flowering plants and peripheral communities. 
Thus, characters increasing power and improving structural integ- 
rity are likely to be primitive, in a statistical sense, within the Cole- 
op tera. 
In summary, adaptive responses to ecological differentiation, in- 
cluding initial exploitation of the substrate zone and shifts back to 
the ancestral surface locomotory zone, account for diagnostic fea- 
tures of the coleopterous prothorax and also for major features of 
variation. 
ABBREVIATIONS USED IN THE FIGURES 
AF — anterior fold 
AFL — anterior flange 
ANFL — anterior notal flange 
APLFL — anterior pleural flange 
ASFL — anterior sternal flange 
Cnd — condyle 
CrS — cryptosternum 
CS — cervicle sclerite 
Cw — cowling 
CxBr — coxal bridge 
EndPl — endopleuron 
Epm — epimeron 
Eps — episternum 
Is Mb — intersegmental membrane 
Lb — lobe 
N — notum 
N pj — notal projection 
PI — pleuron 
PlAph — pleural apophysis 
PNFL — posterior notal flange 
Pl-S — pleuro-sternal joint 
RFM — rim fold margin 
S — sternum 
S Aph — sternal apophysis 
SL pj — sternellar projection 
S pj — sternal projection 
Tn — trochantin 
Zf — zone of fusion 
Bibliography 
Arnett, R. H., Jr. 
1967. Present and future systematics of the Coleoptera in North 
America. Ann. Ent. Soc. Amer. 60: 162-170. 
Bock, W. J. 
1965. The role of adaptive mechanisms in the origin of higher levels 
of organization. Syst. Zool. 14: 272-287. 
Brundin, L. 
1972. Phylogenetics and biogeography. Syst. Zool. 21 : 69-79. 
Crowson, R. A. 
1955. The natural classification of the families of Coleoptera. Natha- 
niel Lloyd & Co., London. 187 pp. 
1960. The phylogeny of Coleoptera. Ann. Rev. Ent. 11: 111-134. 
