1878.] 155 



to find its moiitli tenanted by a colony of a large species of Acarus, 

 and I also found some individuals of the same (or an allied) species 

 in the mouth of one of the specimens from Mr. Murray's collection. 



Another and much smaller Acarus has, moreover, found a less 

 easily visited feeding ground, on (or rather in) the body of Seliocopris 

 Mouhohis ; this spot is the prothoracic stigmata. 



On examining an individual of Seliocopris Mouhotus, whose thorax 

 had become separated from the body, in Mr. Murray's collection, I 

 was surprised to find fifty or sixty individuals of a small Acarid at- 

 tached to each of the two prothoracic stigmata, and, on taking to 

 pieces the other specimens of the gigantic Lamellicorn, I found the 

 corresponding stigmata to be tenanted in a similar manner. No doubt 

 this species of Acarus, which is small and very depressed, is able to 

 penetrate between the presternum and mesosternum just at the ex- 

 treme anterior part of the middle coxal cavities, for this spot is quite 

 near to the prothoracic stigma, and on a movement of extension of the 

 head and thorax being made by the Heliocopris, the Acarid could 

 easily find entrance at the spot I have mentioned. I should not be at 

 all surprised if it be found that this Acarid is a species specialized for 

 this mode of life. 



Heliocopeis Mouhotus, n. sp. 

 Major ; Jigura H. gigantis (Bates), multo major, niger, nitidus, 

 sithtus ritfo-liirsiitus ; elytris sat crehre punctatis, evidenter striatis, in- 

 terstitiis liaud conveocis ; prosierno post coxas liaud Jiirsuto ; capite 

 magno. 



Mas, major ; capite ad oculos hand constricto, lateribns in medio 

 utrinque cornu erecto, lato, apice emarginato, inter cornua simpliciter 

 arcuatim carinato. Prothorace angulis anteriorihus leviter prominulis, 

 utrinque anterius loho prominulo sub-hamato ; supra antice longius per- 

 pendiculari, medio lamina elongata, sub-horizontali, acuminata; basi 

 utrinque area Icevigata. Long.QQ — 65 mm.; lat.prothoracis, 36 mm. 



Mas, minor ; capite ad oculos constricto, sed hand angulato, vertice 

 in medio transversim fortiter elevata, elevatione in medio emarginata. 

 Frothorace prope angulos anteriores hand vel vix angulato, anterius bre- 

 viter perpendiculari, dot^so ante medium carina transversa elongata, 

 medio anterius sub-angulatim prominula ; undique fortiter rugoso. 



Long. 50 — 54 mm. ; lat. prothoracis, 29 — 31 mm. 

 Fem. ; capite ad oculos constricto, haud angulato, vertice in medio 

 elevata, trituberculata, tuber cutis later alibus minutis ; frothorace prope 

 angulos anteriores haud angulato, anterius breviter perpendiculari, dorso 

 ante medium carina transversa elongata, utrinque sinuata, in medio late 

 rotundato. Long. 54 mm.; lat. prothoracis, 31 mm. 



Hab. : Laos, Cochin China. 



Thoruhill, Dumfries : September 28tk, 1878. 



