DIPHAULACA. 263 



Pam. GALEEUCID^B. 



Subfam. HALTICINM 



In attempting to monograph the Halticinee of Central America I am fully aware of 

 the great and many difficulties which have to be overcome — the great amount of 

 material before me, the structural characters of the group which have to be taken into 

 account, many of which are perhaps rather dubious when used as a guide to determi- 

 nation of genera, and, most of all, the difficulty one has to encounter in trying to 

 arrange the vast material into some state of order so as to assist as much as possible 

 the student in the determination of this difficult group. To solve this perplexing 

 problem would have been a more arduous undertaking, had not the genial Chapuis 

 marked out a basis for future studies in his continuation of Lacordaire's ' Genera des 

 Coleopteres.' In the present monograph of the Halticinse of Central America I prefer, 

 however, not to follow entirely that author's arrangement, but adopt the plan followed 

 by von Harold in his description of Colombian Halticinse (Coleopterologische Hefte, 

 xiv.), dividing the entire group into two sections, viz. those in which the thorax shows 

 a more or less distinctly marked transverse groove, and others in which the thorax is 

 entirely without that character. The first section can then again be divided into 

 genera with open and genera with closed anterior coxal cavities. The first of these 

 characters, the thoracic groove, seems to me of quite as great importance as the state of 

 the anterior cavities, and is at all events easy of recognition, which is of great value in 

 so numerous and difficult a family. 



Section 1.— Thorax with a transverse groove, the latter limited and interrupted at 



the sides. 



a. Anterior coxal cavities open. 



DIPHAULACA. 



Diphaulaca, Clark, Journ. Ent. ii. 1865, pp. 377, 386; Chevrolat in D'Obi^n. Diet. univ. Hist. 

 Nat. v. p. 46. 

 The differences between this and the next genus (Lactica), to which it is closely 

 allied, has been well pointed out by von Harold in the ' Coleopterologische Hefte,' to 

 which I simply refer here. Clark's definition of the genus is therefore only partly 

 correct ; and the species he describes cannot belong all to Diphaulaca, on account of 

 the punctuation of the elytra, which is arranged in regular striae and not confusedly 

 punctate as some of Clark's species are. The anterior angles of the thorax in 

 Diphaulaca are acute and turned outwards, the claws are appendiculate, and the palpi 

 have the terminal joint pointed and slender. Only a single species has been described 

 previously from Central America, the others from South America. 



