384 Annals Entomological Society of America [Vol V,. 
consists of an anterior and posterior part, fused or articulated 
at the point o. A heavily chitinized plate, t, connects the 
entire lower halves of the cost superiores. 
The setz consist of four very long, slender, solid rods, the: 
bases of each being enlarged and forming an elongated cone, , 
s,—s. Two of these cones lie on either side of the box, one: 
pair being supported by branches from the piece 1. The other 
pair of cones is supported by a heavily chitinized elongated 
structure, x, arising from the posterior surface (base) of the: 
framework, and standing up within it, its anterior end being . 
just above the point of articulation of the upper and lower 
halves of the cost, and lying free within the cavity. Between 
the conical bases of the sete and arising from the clavus is a 
short cone-shaped organ, lying just below the pharynx and 
cesophagus and possibly serving to protect them. 
The four setaze come together at the clavus and are appressed 
to form a tube. This tube then passes backward into a long 
transparent pocket, the labial cavity, c. This pouch lies in the 
body cavity next to the ventral body wall, running back to the 
fourth segment. The tube extends the entire length of the 
labial cavity and forms a loop, returning to the point of entrance 
and passing out of the body through the labium. 
The labium, z, is an external organ and does not have much 
movement except a slight backward and forward motion. It 
is a heavily chitinized, more or less heart-shaped structure, the 
lateral halves of which, originally separate, have been fused 
together. The sete pass through the center and upper part of 
the labium and pass out of the lower or apical end. The 
labium is heavily musculated, and at its external opening a 
cross section shows a ridged or serrated structure. 
ALIMENTARY CANAL. 
(Plate XXVIII, Figs. 3 and 4.) 
The oesophagus is long and slender, widening out as it 
approaches the proventriculus. It is strongly musculated with 
circular muscles, the inner wall consisting of a layer of small 
single-nucleated cells. Passing upward and backward it goes. 
through the cesophageal commissures and enlarges into the 
proventriculus. Back of the proventriculus is the ventriculus. 
proper. 
