97 



common base, basal segment large and swollen, bearing an ex- 

 tero-lateral prolongation which somewhat resembles in size and 

 ai)pearance the small cylindrical Snd and minute pa])illif()rm 

 ;3rd segments. 



Thorax. — The thoracic segnnents are mnch coalesced and ill- 

 defined ; the ventral tnbercles of the ]st a})proximate to the 

 month, folding aronnd the latter ; dorsally this segment bears 

 a pair of small papilliform stigmata, the ventral tnbercles of 2na 

 aii<l '3rd segments are well-developed and bear numerous set^e 

 aud booklets. 



Abdomen. — A slight constriction separates the thoracic and 

 abdominal regions, the latter consists of 9 segments, manv of the 

 ventral tnbercles are so well develojied as to function as pseudo- 

 pods. lst-5th segments, pseudopods well <leveloped, bearing nu- 

 merous seta? and booklets ; Gth-Tth segments, pseudopods and 

 booklets less developed : 8th segment bears a pair of small, point- 

 ed ventral and tAvo pairs of large lateral pointed tul)ercles, pseu- 

 dopods absent. 9th segmeut bears a pair of lateral pointed tuber- 

 cles and is terminated by the strongly chitinized stigmatic tubes, 



Puparium. — (! x 3 mm., dark, dull testaceous, thoracic stig- 

 matic tubes shining testaceous one-eighth the total length of ])u- 

 parinm, apices rather swollen. Posterior stigmatic tubes shining 

 testaceous one-sixth total length, apex fringed. The three pairs 

 of postero-lateral tubercles distinctly visible, as in the larva. 

 The puparium bears a strong general resemblance to that of 

 Volurella ohesa but both thoracic and posterior stigmatic tubes 

 are much longer relatively in t^yrliia. 



The various stages in the life-history of this fly are figured 

 on Plate 4, as below: 



Fig. 5. Egg of Syritfa occanira Mncq. — x 100. 



Fig. 6. Portion of chorion showing thickened areas of the 

 membrane. — x 400. 



Fig. 7. Adult larva of S. oreanira (dorsal view) ; a, thoracic 

 stigma; b, antenna; c, posterior stigmatic tube. 



Fig. S. Anterior extremity of larva (ventral view) ; a, basal 

 antenna! segment; a\ lateral process of same; 

 a-, 2nd antennal segment ; a'''^ minute 3rd seg- 

 ment ; b, buccal cavity; c, 1st thoracic pseudo- 

 pod ; d, 2nd thoracic psendopod. — x 30. 



Fig. 9. Puparium ; a, thoracic stiginatic tube. — x 12. 



