FOLSOM: MOUTH-PARTS OF ANURIDA MARITIMA. 91 
last five abdominal segments, and by longer appendages, of which the 
antenne and legs show traces of segmentation. It is approximately 
the stage of Figures 42 and 47 of Claypole. 
At Stage 3 (Plate 1, Figure 3) the ventral surface of the embryo is 
almost flat, preparatory to involution; the legs are decidedly longer, 
and the fundament of the proctodzum is distinct. Figures 43 and 
43° of Claypole belong near this stage ; also Figure 10 of Ryder (’86), 
likewise for Anurida maritima. 
During Stage 4 (Plate 1, Figure 4) the germ band is folding into the 
yolk, the fold beginning anteriorly and continuing backward. The 
antenne and legs are long and stout. My figure shows a stage a little 
later than that of Figure 44 by Claypole. 
At Stage 5 (Plate 1, Figure 5) the involution has reached the centre 
of the egg, the antennz and legs are distinctly segmented, the mouth- 
folds are conspicuous, and the dorsal organ has shrunken considerably. 
Stage 6 (Plate 1, Figure 6) is much like the last, except that the 
head and tail of the embryo have approached each other. The dorsal 
organ is much reduced and somewhat flask-shaped. This is the stage 
of Ryder’s Figure 7. 
At Stage 7 (Plate 2, Figure 7) the eyes are first recognizable as five 
black circular patches on either side. Figure 45 of Claypole represents 
this condition. 
Stage 8, which I have not figured, differs externally from the last in 
that the number of eyes is no longer evident, it being obscured by a 
suffusion of pigment. The degenerating dorsal organ now disappears by 
resorption. 
Stage 9 (Plate 6, Figure 41; also Claypole, Figure 48) refers to the 
newly hatched insect. Before this period, movements of the insect may 
be seen through the egg membranes. If eggs have been kept dark, — 
the normal condition, — the emerging insects are white, excepting the 
eyes ; if exposed to sunlight, however, the embryos become blackish- 
blue long before hatching. At emergence the external clothing of setz 
is complete, and the mouth-parts are fully formed. 
Procephalic Lobes. 
The fundaments of the procephalic lobes are two isolated thickenings 
of the blastoderm, which are the first of the paired fundaments to ap- 
pear. Each procephalic fundament is lenticular in form and rapidly 
increases in thickness and area. In the earlier stages the procephalic 
