128 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
my figures (Plate 3, Figure 20; Plate 5, Figure 29) will show that 
practically the entire ventral surface of the head is labial in origin, be- 
cause the original bases of the second maxillz extended quite to the first 
pair of legs; an inconsiderable, if any, portion of the germ band inter- 
vening (Figure 21) between them. 
At Stage 8 the mouth is nearly closed (Plate 5, Figure 34) by the 
overgrowth of the combined second maxillz and mouth-folds. 
In the adult (Plate 7, Figure 43) the apical lobes, although in con- 
tact mesally and stoutly chitinized, are readily separable and may be 
depressed and elevated by muscles homologous with those of Orchesella, 
the hinge lines being shown at sut. Shortly before hatching, hypodermis 
cells evaginate singly to form the external setz of the head. 
In the development of the labium, as I have traced it, neither galea 
nor lacinia becomes differentiated ; but the terminal lobe is equivalent 
to the head of the first maxilla, and therefore represents the common 
fundament of galea and lacinia, the second maxilla not passing the 
biramous stage. All of the labium behind the terminal lobe represents 
not only the stipes and cardo of the first maxilla, but also the mentum, 
submentum, and gula of the Orthopteran labium, —an important 
conclusion. 
In Orchesella (Folsom, ’99, Plate 3, Figure 24) mentum, submentum, 
and gula appear to be indicated, but the development in Anurida throws 
no light upon the structures which I suggested might be modified palpi. 
Packard (’71, p. 17) in describing Isotoma says, “I was unable at 
this or any other period to discover any traces of the second maxille. 
Though existing in a very rudimentary state in the adult, I could not 
detect them after repeated attempts, but do not doubt but that a more 
skilled observer would have made them out. Indeed, it is a most diffi- 
cult thing to discover their rudiments in the adult ; I failed, at the time 
these observations were made, to detect them, though since then I have 
succeeded in making out their structure and relation to the surrounding 
parts of the mouth.” Asa matter of fact, he (Plate 3, Figure 13) has 
evidently figured the second maxille, which I know to be present in the 
genus, and in the passage quoted he doubtless referred to the super- 
lingue (“ paraglosse ”), which Lubbock also #73, p. 66) termed “second 
maxille.’’ Ryder (’86, Plate XV. Figures 7, 9, 10), too, repeated the 
mistake in Anurida. 
Claypole (98, Plate XXIII. Figures 40-44, 46, 47) represents the 
fundaments as simple papille without distinguishing the palpi, which 
are, however, obscurely indicated in Figures 43 and 47. 
