638 



E. N. PAVLOVSKY 



contracted thoy prc^ss the upper wall of the tube to the convex 

 under-surface of the same. The antagonists of these muscles 

 are the muscular bundles, extending from the upper surface 



Text- FIGS. 8-11. 



From a series of transverse sections of the head of a larva of the 

 first stage. Zeiss, ob. AA, oc. 0. 



Fig. 8. — Transverse section through mouth-parts. ^landibles (md) 



without mner canals ; mx, maxilla ; a, antenna ; lb, labium. 

 Fig. 9.- — Transverse section at level of union of mandibles with 



head. The oral aperture (ap) with its spiny inner surface is 



visible. 

 Fig. 10. — Section near the region of antennae («)• Suctorial 



apparatus — sphincters (s^) and dilatators (dl^), attending fore 



part of intestine. 

 Fig. 11. — Section at level of cephalic nervous ganglia {soe, spe). 



Fore-gut with dilatators {dL) and sphincters (So) of pharj-nx. 



of the intestine to the upper wall of the head (Text-fig. 10, dlj). 

 When contracted they lift the upper wall of the tube, and, 

 therefore, increase its cavity ; these levators might be called 

 suctorial muscles. There are several pairs of them. 



