150 ENTOMOLOGY 
(Fig. 193), is the beginning, or fundament, of the hind gut. 
At the anterior end of the germ band is a pair of large 
procephalic lobes (Vigs. 192, 194), which eventually bear the 
lateral eyes, and immediately behind these are the fundaments 
of the antenne. The fundaments of the primary paired ap- 
pendages are out-pocketings of the ecto- 
Fic. 194. 
dermal germ band, and at first antenne, 
mouth parts and legs are all alike, except 
wo. in their relative positions. Behind the 
wt antenne (in Thysanura and Collembola 
“ead at least) appears a pair of rudimentary 
“ appendages (Fig. 194, 1) which are 
ee thought to represent the second antennz 
oy of Crustacea; instead of developing, they 
pt ---43 disappear in the embryo or else persist in 
Pascal, the adult as mere rudiments. In front of 
ce as these transitory intercalary appendages 1s 
Saar the mouth-opening, above which the 
r i ies labrum and clypeus are already indicated 
(94 ena by a single, median evagination. Behind 
gis oF the mouth the mandibles, mawnille and 
labium are represented by three pairs of 
Ventral aspect of germ Z : ; - = 
band of a collembolan, fundaments, and in Thysanura and Col- 
tenn: Ht utdcws. lembola a fourth pair is present to jorm 
antenna; ala, abdominal 
appendages; i, intercalary the superlinguz ( Fig. IL@)ES. sl ee already re- 
appendage; /, labrum; Ji, + : ae : 
(ef Jahial’ .appendage.. Lerred to..” Next im ~order are the thice 
m, mandible; ma, max- 
illa; p, procephalic lobe; 
br, proctodeum; -f*, jn many cases, paired abdominal appen- 
thoracic legs, oe i : ; 
dages (Figs. 194, 196), indicating an 
pairs of thoracic legs (Fig. 194) and then, 
ancestral myriopod-hke condition; some of these abdominal 
limbs disappear in the embryo but others develop into abdomi- 
nal prolegs (Lepidoptera and Tenthredinidz ), external genital 
organs (Orthoptera, Hymenoptera, etc.) or other structures. 
The study of these embryonic fundaments sheds much light 
upon the morphology of the appendages and the subject of 
segmentation. 
