PSYCHE 
VOL. XXXII. AUGUST-OCTOBER 1925 Nos. 4-5 
THE EXTERNAL ANTATOMY OF THE HEAD AND 
ABDOMEN OF THE ROACH, PERI PLAN ETA 
AMERICANA' 
By G. C. Crampton, Ph. D. 
Massachusetts Agricultural College, Amherst, Mass. 
Despite the fact that the very sight of a roach engenders in the 
minds of many people a feeling of repugnance and disgust, while 
others consider that roaches are too insignificant to be worthy of 
one’s serious attention, roaches are nevertheless extremely “an- 
cient and honorable” creatures in the sight of the great mother 
Nature. In fact they were her favorite children some hundreds 
of millions of years ago when the coal measures were being laid 
down in Carboniferous times, and their fossil remains are so char- 
acteristic of the Carboniferous strata that the Carboniferous per- 
iod is frequently referred to as the “age of cockroaches,” just as 
the much later Jurassic period is referred to as the “age of rep- 
tiles,” etc., from the dominant fauna of the periods in question. 
We are accustomed to look upon the hills as “eternal,” while 
the occurrence of so frail a creature as a roach is regarded as mere- 
ly one of Nature’s passing incidents; but, frail as roaches are, the 
roach type has persisted but little changed from the remote Car- 
boniferous period, while in the meantime, mountian ranges have 
risen and been leveled again, and the whole face of the landscape 
has changed, and changed again. During the time in which the 
roach type has been in existence, the great dinosaurs have come 
and gone, and birds, mammals, and flowering plants have arisen 
and developed their myriad profusion; but amid there ceaseless 
comings and goings, the roach type has pursued the even tenor 
of its way practically unaffected by the passing of the ages. It 
is therefore of some interest to study the makeup of an organism 
Contribution from the Entomological Laboratory of the Massachusetts 
Agricultural College, Amherst, Mass. 
