290 
Psyche 
[December 
molds the developing organism so uniformly true to type, and of 
the condition which now and then may cause the development of 
an individual in some detail to halt a little short of, to over-run, 
or otherwise to deviate from its due course. 
It is truly an obligation, very generally neglected by Amer- 
ican entomologists however, to record each example of insect 
teratology simply and directly, just as it is observed; but the 
fulfilment of this obligation is by no means accompanied by any 
additional obligation to offer at the same time an explanation or 
interpretation of the phenomenon. Indeed, in the present state 
of our knowledge of such phenomena any attempt to interpret 
individual examples is rarely demanded, or even scientifically 
justifiable. 
THE SECOND ABDOMINAL PLEURITE IN THE HIGHER 
COLEOPTERA 
Ry W. T. M. Forbes, 
Cornell University, Ithaca, New York. 
It is generally recognized that the first sternite of the ab- 
domen is membranous in all the holometabolous insects. As to 
the first pleurite and the second segment there takes place a 
gradual reduction, which reaches such a stage that in the ma- 
jority of Coleoptera the first two segments are represented by a 
more or less membranous dorsal and spiracular region only. 
The usual statement is that the first segment of the ab- 
domen has atrophied, and that the second is ventrally absent 
and laterally fused with the third. An examination of fresh 
specimens shows that this is not strictly the case. In fact the 
second pleurite may disappear in at least two different ways. 
In the Bostrychiformia (Fig. 1, A) the first stage seems to 
have been an infolding of the whole subspiracular region of the 
first two segments, so that the hind coxa comes to lie against 
the anterior edge of the third segment or even overlap it some- 
what. In this way the two segments are completely buried from 
view, and their sclerites become more or less completely de- 
