458 INSECTS ABROAD. 



light be insufficient, the whole of he tissues appear to be dull 

 velvety black. In point of fact, the eal colour of the head, 

 thorax, abdomen, and legs is Prussian green, so deep and 

 rich that at first sight the insect will probably be set down 

 as a black one. The wings are shining brown, and the 

 antenna) are black for half their length, and yellow for the 

 remainder. 



The reason for giving the name of Pepsis to these insects 

 is to me one of the many insoluble mysteries in connection 

 with insect nomenclature. The word Pepsis is Greek, and 

 primarily signifies " digestion" or "concoction," and when used 

 in reference to wine it signifies " fermentation." The term is 

 familiar to most persons in forming part of the word " dys- 

 peptic," i.e. difficult digestion. I very much wish that all 

 persons who give a name to any new species, whether it be 

 animal or vegetable, should be bound at the same time to 

 explain that name and state their reasons for giving it ; and I 

 should like to abolish, once and for all, the custom of giving 

 to a new species the name of any human being. Every name 

 ought to designate some characteristic, and that can never be 

 done under the system that is so largely followed. 



On Plate IX. Fig. 1 is shown a Brazilian species, called, on 

 account of its size and strength, Pepsis heros. 



Like the preceding insect, it looks at first sight as if it were 

 black, the colour being in fact the deepest blue, with a sort of 

 velvet-like lustre. The wings are brown and glossy, and the 

 legs black. 



The insect which is here given is, I believe, a new species and 

 hitherto undescribed. On account of the general richness of 

 its colour, Mr. Smith has given it the specific title of nigrescens, 

 i.e. " blackish." It is a native of Demerara. The colour of the 

 insect is black, with a thick velvet-like fur on the head and 

 thorax. The legs are long, and without spines. The reader 

 will notice that the tibia) of the hind legs are much flattened, 

 this being a peculiarity common to the male sex throughout 

 the whole genus. The wings are very beautiful. Their gene- 

 ral colour is black, but they are adorned with many bold 



