6 GEO. H. HORN, M. D. 



ORSODACBTA Latr. 



In " Eutomologica Americana," vol. i, p. 9, while giving the syn- 

 onymy of the species described by Newman, will be found a list of 

 the synonyms of Orsodacna atra Ahr. 



In the few words which follow I hope to make clear the relation- 

 ship of the names to each other, and as briefly as possible describe 

 the varieties which have caused the multiplication of names. 



O. atra Ahrens (Donacia), Nov. Act. Halens. i, p. 46 ; LaconL, Mon. p. 86. 

 Color entirely piceous, including the legs. 



Var. tibialis Kby., Fauna Bor. Am. p. 221 ; inconstans Nm. Ent. Mag. v, p. 391. 



Entirely piceous, e.Kcept that the tibiae and base of femora are 

 more or less testaceous. 



Newman recognized as varieties of his species certain forms which 

 are sub-varieties of trlvitUda, hence his name. 



Var. luctuosa Lac. loc. cit. p. 72. 



Piceous, thorax reddish, with a central discal spot of variable size 

 piceous. 



Var. hepatica Say, Joiirn. Acad, v, p. 281 : riificoUis Newm., Ent. Mag. v, p. 391. 



Piceous, thorax entirely red. 



The specimen described by Say was evidently slightly immature, 

 that by Newman fully colored. 



Var. vittata Say, Journ. Acad, iii, p. 430; Lacord., Mon. p. 71 : armeniacse Germ., 

 sp. nov. p. 526. 

 Piceous black, thorax orange-yellow, each elytron with a narrow, 

 slightly oblique, yellow stripe. 



Var. trivittata Lacord., Mon. p. 71 ; tricolor Mels., Proc. Acad. 1847, p. 160. 



Color in great part yellowish, with slight reddish tinge to the 

 thorax ; elytra with a narrow sutural piceous stripe and a lateral 

 piceous border, which at middle is much dilated and again narrowed. 



Occasionally the occiput is piceous. 



The elytra may become entirely yellow. One specimen in my 

 cabinet has merely a slight piceous area at tip. 

 Var. Childreni Kby., Faun. Bor. Am. p. 221. 



In great part piceous, each elytron with a humeral and apical 

 yellow spt)t of variable form and size. 



The legs are either piceous or testaceous, depending on the extent 

 of either color on the elytra. 



The yellow elytral spots may become so extended as to produce ii 

 design resembling closely that of trivittata, but for tho.se who desire 



