— 26 — 



lopment of Smicra sispes, acccrding to HENNEGUY (1). — Vide 

 fig. 3 B, and 4 A. — A great mâny nuclei can now be seen 

 lying close to the egg wall while a nucleolus is seen as the 

 large cell in the posterior end of the egg. 



The youngest embryo I hâve seen is figured in fig. 4 B and 

 C; it is 0,192 mm long and simply bag-shaped ; only dorsally 

 is seen a furrow separating a head from the rest of the body; 

 on the ventral side, is seen a transversal fissure anteriorly, the 

 mouth, which leads into a narrow gut which terminâtes in an 

 enlarged midgut without any outlet; on the ventral surface, 

 there is a heartshaped aperture below the mouth, leading into 

 a pair of glandiform organs, surely representing the salivary 

 glands . 



RlMSKY-KoRSAKOW mentions that no anus is présent, but this 

 is an errer; as seen en my figure 4, an anus can easily be disco- 

 vered, and from this anus an endgut leads in between some 

 large body cells where it disappears without having any con- 

 nection with the midgut. Any other organ is not présent in the 

 larva. RlMSKY-KcRSAKCW mentiens to be sure a little ganglion 

 in frent, but I hâve net been able to cenfirm this statement. 



oo ^ 

 9P00 



D 



Fig. 4. — Prestwichia aquatica LUBB. 



A. Egg. — B. C. D. Embryoes. — E. Free larva. — (Fig. C is seen from the ventral side, 



the others from the side and in eut.) — (Ail figures enlarged X 1 50.) 



(I) Les Insectes, 1904, pp. 314-337. 



