44 Annals Entomological Society of America (Vol. VIII, 
two parts, which are of about the same length. The 
distal half is a long, heavily chitinized, hollow spine, while the 
proximal half is broader, hollow and not as heavily chitinized. 
Cross and longitudinal sections show a distinct lumen extending 
thruout its length (fig. 26). At the very tip of the spine it 
is impossible however to be sure that an opening is present. 
If such an opening is present then it may serve as an exit for the 
secretions from the glandular tissue within the basal half of the 
piercing organ. If the lumen is not a duct for the secretions 
but a blind tube, then one can explain its presence on the basis 
that it is the place formerly occupied by the hypodermal cells. 
which formed the cuticle of the spine. 
Cross-sections of the pharynx show how the asymetrical 
piercing organ passes along the cephalic side of a left lateral 
extension of the pharynx (fig. 40 and 41). This left lateral 
extension is cephalad of the paired extensions over which the 
maxillary sete pass, and only occurs on the left side. In the 
Tubulifera the left maxillary guide helps to form this extension 
(fig. 53). 
There are large muscles attached to the proximal end of the 
asymmetrical piercing organ. These muscles connect with 
the dorsal aspect of the head-capsule and on contraction 
pull the asymmetrical piercing organ (J. md.) into the 
mouth-cone. The majority of the specimens examined showed 
the piercing organ protruding from the concave side of 
the labrum (lr.). Apparently this is its normal position and 
it is evidently used in making the first puncture thru the 
outer cells of the plant tissue. After this puncture is made 
it is probably withdrawn into the mouth-cone, and the 
long maxillary sete are then used to puncture the inner and 
deeper cell-layers. The withdrawal of the asymmetrical 
piercing organ from the tip of the mouth-cone also permits 
the plant juices to pass into the pharynx. 
On the right side of the mouth-cone a piece (r. md.) is found 
which is homologous in position to that of the left, asymmetrical 
piercing organ (fig. 27). In all cases this piece arises adjacent 
to the front, between the clypeus and the right maxillary 
sclerite, and extends to the right cephalo-lateral margin of the 
pharynx and unites with the same (fig. 40). This union is. 
indicated by a distinct suture in cross-sections of the pharynx. 
