112 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
such as are shown in Plate 7, Figures 46-50, which successively repre- 
sent sections in more posterior planes. 
Figure 46 shows the right maxilla (mz.") sectioned in front of its basal 
opening and lying free in its pharyngeal pocket ; it also shows the stout, 
superficial chitinous stalk (pd.’) in its hypodermal groove. Figure 47 
represents the beginning of an evagination (plz.) of the dorsal wall of 
the pocket, which grows down between the maxilla and chitinous stalk. 
Passing back, the intruding hypodermal fold expands, as in Figures 48 
and 49 (plv.), until it almost encloses the stalk. Finally, in the region 
of the maxillary aperture (Figure 50), and on account of its obliquity, 
adductor muscles (mw.) are enabled to pass directly from the inner wall 
of the stipes to the chitinous stalk (pd.’). They are not attached di- 
rectly to the stalk, but to an intervening cuticula (cta.) ; this, however, 
amounts to the same thing, because the cuticula and stalk become fused 
together at about Stage 7, and hardened into a single piece. It should 
be stated that the hypodermal cells which formed the intervening 
cuticula, as well as those which formed the stipes, are seen in em- 
bryological life only; they disappear at the origin and insertion of 
muscles. 
At Stage 7 the end of each stalk is already feebly fused with the end 
of the cardo to form an articulation (compare Plate 4, Figure 25, with 
Plate 6, Figure 38, atc.). This is a simple process, as both cardo and 
stipes are superficial and contiguous structures. In the adult Orchesella 
(Folsom, ’99, Plate 2, Figure 10, /¢g.') a long ligament unites them, and 
I mentioned a distinct suture as possibly indicating the end-to-end union 
of two ligaments, which doubtless occurred. 
The lingual stalks, then, are quite independent of the lingua in origin, 
except that they are thickened cuticular structures continuous with the 
lateral cuticula (Plate 7, Figure 45, cht.) of the lingua. When dissect- 
ing out the lingua at Stage 7, it frequently breaks away from the stalks 
at the sutures (swt.) shown in Plate 4, Figure 25 ; these sutures later 
become obliterated, however. 
The lingual stalks of Collembola have been mentioned by several 
authors, for example, de Olfers (’62, p. 18) in several genera, Tullberg 
(72, Taf. IV., Figur 17) in Tomocerus, and v. Stummer-Traunfels 
(91, Taf. I. Figur 7) in Tetrodontophora. I have seen them myself 
in all the more common genera; they undergo but little modification 
within the order. 
As to the development of the lingua and superlinguz in other insects, 
very little has been written. Packard (’71, p. 17), as quoted on page 
