122 



REPORT UPON A COLLECTION OF 



Morphological characteristics. Adult female about 1 mm. long, some- 

 what elongate oval, in general resembling O. litorosa; derm membranous 

 except for the pygidium and the lateral margins of the abdominal seg- 

 ments. Lateral margins of the segments with many small ducts. 



Fig. 43. rO donas pis fistulata n. sp. : A, pygidium of adult ; B, pygidial margin of 

 first stage ; C, antenna of first stage. 



Pygidium (Fig. 43A) without lobes or paraphyses but with a median 

 notch which is continuous with a tubular invagination which extends into 

 the pygidium, and from the inner extremity of which there arises a cluster 

 of slender ducts. Tubular ducts small, extremely numerous. Anal open- 

 ing quite small, placed well toward the anterior margin of the pygidium. 

 Ventral side with a few ducts, these confined to a broad marginal zone. 

 Circumgenital pores present, numerous, arranged in three more or less 

 confluent groups. _ 



Second stage with the pygidium practically as in 0. litorosa but with 

 the tube present and with but the first pair of paraphyses developed. 



First stage with the antennae (Fig. 43C) quite short and stout, 

 5-segmented, the third segment not elongate, and the terminal segment 



