388 Mr. H. W. Bates on the Longicorn Coleoptera 



fulvam includente : maris segmento terminali ventrali obtuso, 

 inermi, angulis penicillatis. Long. A\ lin. c? $ . (3 exempl.) 



Head reddish brown, streaked with tawny, and with two di- 

 vergent tawny Unes on the crown. Antennse reddish, bases of 

 alternate joints from the fourth or sixth ashy. Thorax chestnut, 

 brown or darker, with six vittse and the under surface ashy- 

 tawny. Elytra rather short and slender, gradually and rather 

 strongly tapering from base to apex; apex sinuate-truncate, 

 both sutural and external angles spinose, the sutural shorter; 

 surface dark castaneous brown, the basal and apical parts sprin- 

 kled with irregular-sized tawny-ashy specks, leaving a broad 

 clear space on the disk of each, in the centre of which is a larger 

 irregular tawny-ashy spot ; apex with an ashy margin of regular 

 width. Body beneath clothed with tawny-ashy pile. Legs 

 reddish ; tibise and tarsi spotted with ashy and black. 



^, Terminal abdominal segment rather elongate, thickened 

 before the apex ; the ventral plate with obtuse angles, from each 

 of which proceeds a line of thick bristles ; dorsal plate simple at 

 the apex, and closely applied to the sloping front margin of the 

 ventral. Fore tarsi with the first joint greatly dilated. 



? . Terminal abdominal segment strongly tapering and notched 

 at the apex. 



Ega, Upper Amazons. 



The very great and striking difference in the accessory genitjil 

 organs between these two closely allied species {Colobothea securi- 

 fera and C. sejunda) merits a few words of especial mention. 

 When I was separating my specimens of Colobothea into species, 

 I placed together all the individuals belonging to these two as 

 one and the same, and could not find anything in their form or 

 markings to warrant their being treated as anything more than 

 mere local varieties, even after I had given them a second exa- 

 mination. A species has so often proved to exist under distinct 

 local forms on the Upper and Lower Amazons, that I concluded 

 this was simply another example of the rule. When I came, 

 however, to separate the sexes previous to describing the species, 

 I discovered the remarkable difference of structure described 

 above, and then noticed the two or three other small points of 

 difference in the general shape and tips of the elytra which I 

 have noted in the descriptions. A pair of elongated horny pro- 

 cesses, which I suppose to be the sheath of the penis, project 

 from between the terminal abdominal segments in two out of 

 the three males I possess; in the third they appear to be with- 

 drawn into the abdomen. It is a remarkable circumstance, that 

 in many families of Lisects which have accessory sexual parts 

 easy of examination, it is found that these differ very con- 

 siderably in structure in closely allied species. It has been 



