164 C. R. Osten Sachen-. 



vein less sinuate ; the abdomen is comparatively longer ; the metanotiim 

 less horizontal, more sloping. 



The Single specimen of Tanypremna opilio 0. S. (Guatemala) 

 from which I drew my description was pasted on a piece of cardboard 

 and did not allow a close examination. A species from Brazil, in 

 the Berlin Museum, with tibiae and tarsi conspicuous'ly annulate with 

 white, belongs, I believe, to the same genus. 



IL Ou Ctenophora and its relatives. 



1. Ctenophora and Tipula; the distinguishing characters • 

 between them. 



Ctenophora and its relatives form quite a natural group among 

 the Tipulina; but it belongs in the number of those groups which 

 it is easier for the eye to perceive than for the mind to dehne. 

 What character, or characters, should a Tipulid have, in order to be 

 called Ctenophora? Pectinate antennae.in the male? But we have 

 the South-American genus Ozodicera, which, to all intents and pur- 

 poses , is a Tipula , although it has pectinate or branched antennae 

 in the male. And on the other band we have the recently described 

 genus Prionota v. d. W., which is a Ctenophora without pectinate 

 antennae in the male. All the distinctive characters which I perceive, 

 between the two groups, are merely comparative; the discovery of 

 an absolute character is as yet a de'sideratum. 



Compared to Tipula, the genus Ctenophora (inthe widest sense), 

 has shorter and comparatively stouter legs; the tarsi are usually 

 shorter than the tibiae, the first Joint of the tarsi is comparatively 

 shorter, that is, about equal in length or but little longer than the 

 four remaining joints taken together; while in Tipula the first Joint 

 is generally considerably longer than the rest of the tarsus; the ungues 

 in Ctenophora are larger. (The legs of Tip. nigra, shorter than 

 those of the other species of the genus, show some approach to those 

 of Ctenophora.) 



The front of Ctenophora is broader, the head much more closely 

 applied to the prothorax; the rostrum as short as, or -shorter than 

 in Pachyrrhina, gibbose in front; the nasus is an obtuse, hairy 

 protection. 



The body of Ctenophora is smooth and glabrous, and the colors 

 usually offer brilliant contrasts of black, red and yellow, which, among 

 the other Tipulina, are approached only by some Pachyrrhinae. 



The antennae in the great majority of the Tipulina, are verti- 

 cillate; while in the Ctenophorae, in either sex, they are never verti- 



