172 Dr. E. L. Trouessart — Synoptical Revision 



the cell and at the lower end as far as thesubmedian nervure, 

 where it is narrower than at the top and slightly curves out- 

 wardly ; a curved row of five subapical white spots. 



Underside. Both wings dusky brown, paler towards the 

 apex and outer margin of anterior wings and crossed by an 

 irregular black line, which, on anterior wings, is narrowly 

 margined externally from the costa to the upper median ner- 

 vule by bluish white, thence internally to the middle of pos- 

 terior wings by dusky white ; outside the black line on both 

 wings is a rather broad, ill-defined, darker brown band ; on 

 anterior wings three irregular bright brown lines cross the 

 cell beyond the middle, the line nearest the base bordered ex- 

 ternally and irregularly with bluish white ; the five white 

 subapical spots as above, beneath which are three nearly 

 obsolete ocelli. Posterior wings beyond the middle with two 

 conspicuous and several other nearly obsolete ocelli ; a bluish- 

 white spot in the cell on the median nervure edged externally 

 with black. 



Expanse of wings 2| inches. 



Nearest to D. dascon and dasyclus, Godman and Salvin. 



XXV. — Synoptical Revision of the Family Halacaridae. 

 By Dr. E. L. Trouessart*. 



The memoir in course of preparation, with the assistance of 

 M. G. Neumann, upon the " Marine Acarina of the shores 

 of France " being unavoidably retarded by the execution of 

 the plates, we think it as well to give at present a synopsis 

 of the actually known species, of the family Halacaridae. 

 We hope in this way to induce the sending of new materials 

 which will enable us to complete the investigation of this 

 marine fauna which is still so little known. 



The number of memoirs relating to the marine Acarina 

 is still but small. We shall content ourselves with giving 

 the following list f of the more important of them, referring 



* Translated from the Bulletin Scientifique de la France et de la 

 Belgique, tome xx. 1889, pp. 224-251. 



t Bibliography. 



1 Gosse, P. H. " On new and little-known Marine Animals " (Ann. 

 Mag. Nat. Hist. ser. 2, vol. xvi. (1855) pp. 27 & 305, pis. 3 & 8). 



2. Hodge, G. ''Contributions to the Zoology of Seabam Harbom\ 

 I. On a new Marine Mite. II. On some undescribed Marine Acari " 

 (Trans. Tyneside Nat. Field Club, 1860, vols. iv. & v.). 



