ANATOMY AND PHYSIOLOGY. 127 
posterior edge of the second ring, which does not 
move so freely within the one just before it as the 
others do. Thesecond abdominal ring, corresponding 
to the seventh larval segment, is the largest of the 
series. In the Vespide, however, it does not predo- 
minate over all the rest to such an extent as it 
does in the Eumenids, where it is large enough 
to receive—emboiter, as the French word neatly 
expresses—all the following rings, like the joimts of a 
telescope. 
The part of the scales which is usually exposed to 
view is set with fine hairs; that which is for the most 
part covered by the preceding ring is not thus clothed 
with hair, but is finely wrinkled, like Morocco leather, . 
on the surface. The connection of the several rings 
is effected by a thin transparent membrane, elastic, 
not muscular. This membrane takes its origin on the 
inner surface of the scales, along the devious, some- 
times obscure, line where the colour of the scale 
changes from dark to light; and, passing forwards, is 
attached to the front edge of the succeeding ring. 
By this arrangement a considerable amount of longi- 
tudinal expansion of the abdomen is allowed for, 
fully equal to one-third of the width of each ring. 
The lateral expansion is much more limited. 
The lateral cusps of the dark belt on the dorsal 
scales mark the points of insertion of two little slips 
of muscle; and two corresponding dots on each of 
the ventral scales give attachment to two more such 
slips, four in all, from each abdominal rmg. They 
pass forwards and outwards to their other point of 
attachment, which is found, less definitely, in the 
soft surrounding parts and in the spur which rises 
