132 



ENTOMOLOGY 



At the anterior end of the germ band is. a pair of large procephalic 

 lobes (Figs. 195, 197), which eventually bear the lateral eyes, and im- 

 mediately behind these are the 

 fundaments of the antennae. The 

 fundaments of the primary paired 

 appendages are out-pocketings of the 

 ectodermal germ band, and at first 

 antennae, mouth parts and legs are 

 all alike, except in their relative 

 positions. Behind the antennae (in 

 Thysanura and Collembola at least) 

 appears a pair of rudimentary 

 appendages (Fig. 197, i) which are thought to represent the second 

 antennae of Crustacea; instead of developing, they disappear in the 

 embryo or else persist in the adult as mere rudiments. In front of these 



[ FIG. 196. Diagrammatic sagittal sec- 

 tion of hymenopterous egg to show 

 stomodseal (5) and proctodaeal (p) in- 

 vaginations of the germ band (g). 

 After GRABER. 



--pr 



FIG. 197. Ventral aspect of germ 

 band of a collembolan, Anurida marit- 

 ima. a, antenna; a l -a*, abdominal 

 appendages; i, intercalary append- 

 age; I, labrum; li, left labial append- 

 age; m, mandible; mx, maxilla; p, 

 procephalic lobe; pr, proctodaeum; 

 *-t 3 , thoracic legs. 



--mx 



FIG. 198. Anterior aspect of embryonal mouth 

 parts of a collembolan, Anurida maritima. a, 

 antenna; I, labrum; Ig, prothoracicleg; li, left funda- 

 ment of labium; In, lingua; m, mandible; mx, max- 

 illa; p, maxillary palpus; si, superlingua. After 

 FOLSOM. 



transitory intercalary appendages is the mouth-opening, above which 

 the labrum and clypeus are already indicated by a single, median 

 evagination. Behind the mouth the mandibles, maxillae and labium are 



