66 DIPTEEA. 



i. 1, t. 20. f. 3 b) ; in the female they are much stouter, and the end is curved. But I 

 have seen in the collection of the Berlin Museum a large female Acanthomera from 

 Brazil, unnamed, dark-coloured like my A. championi ; it has the last joint of the palpi 

 button- or club-shaped, and a beak-like protuberance on the face. Must it be taken 

 for a Rhaphiorhynchus % 



If all the Acanthomerce existing in European collections could be brought 

 together, it would perhaps be an easy matter to draw comparative descriptions, and 

 to unravel the confusion now existing in books and collections. Until such a mono- 

 graphic work is rendered possible, the hints and remarks which I have given, the result 

 of notes taken for several years past in the principal museums of Europe, may be of 

 use to the future describers of new species ; nevertheless it will remain a difficult task 

 to describe new Acanthomeridae. 



The species of this family hitherto found occur within the tropics, in South America 

 and Mexico. I have never seen specimens from the West Indies, nor are any mentioned in 

 existing publications; two specimens in the British Museum are labelled "Trinidad," 

 an island which is so near the coast of South America that, zoo-geographically, it forms 

 a part of that continent. The statement that Thunberg's Pantophthalmus tdbaninus 

 comes from the West Indies, therefore, still requires confirmation. 



Mr. Champion tells me that Acanthomerce are found in the forests, alighting on 

 trunks of trees. 



EHAPHIORHYNCHUS. 

 Rhaphiorhynchus, Wiedemann, Dipt. Exot. p. 59 (1821). 



l. Rhaphiorhynchus planiventris. 



Rhaphiorhynchus planiventris, Wiedem. Dipt. Ex. p. 60; id. Aussereur. zweifl. Ins. i. p. 106, t. 1. 



f. 4 & ii. p. 622 \ 

 (?) Rhaphiorhynchus planiventris, Macq. Dipt. Ex. i. 1, p. 170, t. 20. f. 3 ((J). 

 Acanthomera bigoti, Bellardi, Saggio &c. App. p. 16, f. 10 ( ? ) 2 . 

 Acanthomera crassipalpis , Macq. Dipt. Ex. Suppl. ii. p. 27, t. 1. f. 3; Bigot, Ann. Soc. Ent. Fr. 



1881, p. 458 (Rhaphiorhynchus) ( ? ) 3 . 



Hal. Mexico, Chinantla (Salle) 2 -, Guatemala 3 ; Panama, Bugaba, Volcan de 

 Chiriqui (Champion). — Guiana, Surinam 1 ; Bkazil. 



I have a male (from Chiriqui) and a female (from Bugaba) ; the female is much 

 darker in the colour of the thorax ; the venter is dark brown, which colour is also seen 

 from the upperside as a narrow margin of the abdomen ; the palpi of the female are 

 much stouter than in the male, and the end is curved ; the fusiform palpi of the male 

 end in a straight point (correctly represented by Macquart, Dipt. Ex. t. 20. fig. 3 b). 

 The second posterior cell is almost closed in the male (as Bellardi figures it), and much 

 more open in the female ; this character seems to be variable (cf. Macq. Dipt. Ex. 

 i. l,p. 170). 



