acanthomerim:. 65 



being closely applied to it. Here likewise it must be ascertained whether the presence 

 or absence of the spine is a constant specific character. 



A peculiar pointed projection of the face, sometimes straight-conical, sometimes 

 curved at the tip, which occurs in some species, was taken by Wiedemann, in connec- 

 tion with a peculiar structure of the palpi, as a character of the genus Bkaphiorhynchus. 

 Later, species were discovered in which this projection exists, while the palpi show the 

 ordinary structure. Is this beak a constant character in the same species 1 If it exists 

 in the female, does it also necessarily appear in the male 1 The latter is the case with 

 specimens of Bhajphiorhynchus planiventris before me. But I have seen in the British 

 Museum a female Acanthomera which I would feel inclined to place with a male in the 

 same collection, but for the beak which exists in the former and not in the latter. 

 There seems to also exist a correlation between the beak and the subfemoral spine. 

 A. magmfica, Walk., A. frauenfeldi, Schin., A. picta, Wiedem., and some unnamed 

 species which I have seen in collections have both the beak and the spines ; they seem 

 to form a natural group, distinguished by a more slender body and more projecting 

 humeral callosities. It remains to be seen whether these coincidences are constant. 



The sides of the abdomen in some specimens have sharp edges, generally beset with 

 a more or less dense fringe of hairs easily rubbed off. These sharp edges are produced 

 by the expansion of the dorsal abdominal plates beyond the membrane connecting them 

 with the ventral plates. In other specimens the sides of the abdomen are blunt, and 

 look as if the sharp edges had been bent under or crumpled. It seems evident to me 

 that this difference is not merely accidental, produced in the process of drying, but that 

 it is a real, specific, or may be generic difference. I believe even that I notice a certain 

 degree of coincidence between the presence of the sharp edges and the absence of sub- 

 femoral spines and of facial projections. This point remains also to be investigated. 

 If a generic subdivision should be attempted, the name Acanthomera should be retained 

 for the group with rounded edges and subfemoral spines, and Pantophthalmus, Thunb., 

 the older name, for the species with sharp edges. 



The breadth of the front in the female should be noted; it seems to be a good 

 distinctive character between closely allied species. The comparative size of the head 

 of the male and the structure of the hind femora, sometimes linear, sometimes attenuated 

 at the base, and slightly club-shaped on the latter half, also offer characteristic differences. 



The arrangement of the stripes and spots on the thorax, an apparent monotony 

 notwithstanding, offers excellent characters for the recognition of the species, and 

 especially for the assorting together of male and female specimens of the same species. 

 They should therefore be carefully described, and, if possible, figured. 



The genus Bhaphiorhynchus is based on the peculiar structure of the palpi, which 

 are stout and pointed, and not linear as in Acanthomera. These palpi, so far as I can 

 judge from male and female specimens of B. planiventris before me, are in the male 

 fusiform, and end in a straight point (correctly represented by Macquart, Dipt. Ex. 



Biol. CENTR.-AMER., Dipt., October 1886. ]c 



