REMARKS ON THE GENERIC CHARACTERS. 353 



of Diaphorus ; the males of Lyroneurus, known to me, show no elongation 

 of the pulvilli of the fore tarsi. The genus Chrysotus contains only 

 small, mostly bright-green species, which cannot be mistaken for any other 

 of the following genera, and which are sufficiently distinguished from Dia- 

 phorus by the already mentioned characters ; the statements made above 

 in regard to the shape of the front, the absence of bristles upon the hypo- 

 pygium, and the absence of the elongation of the pulvilli on the fore tarsi 

 of the male, will help to recognize whether a given species, unless its 

 female alone is known, is to be reckoned to Chrysotus or to Diaphorus ; 

 as to the female, the structure of the front, the form of the wings, and the 

 greater or smaller slenderness of the feet, have to guide us in its location. 

 Striking is the very different form of the third joint of the antennae of the 

 different species of Chrysotus in North America. The species of Teucho- 

 phorus resemble more or less the smallest species of Chrysotus, are how- 

 ever very easily distinguished in the male sex by the somewhat laterally 

 compressed abdomen, by the feet which are beset with single, scattered, 

 strong bristles, and by the crooked and variously adorned hind tibiae ; 

 moreover, in all the known males of Teuchophorus there is a large black 

 swelling on the costa before the tip of the first longitudinal vein, which is 

 altogether an exception in the genus Chrysotus. More attention is neces- 

 sary in order to recognize the females of Teuchophorus ; the best guide 

 in this case is the steep position of the posterior transverse vein, the anterior 

 end of which is nearer to the basis of the wing than the posterior end, and 

 the comparatively small antennae, the arista of which is somewhat less 

 approximated to the apex than in most of the species of Chrysotus. The 

 genus Sympycnus contains only small, mostly but little shining species, 

 which are characterized by the smallness and the distinct pubescence of 

 the third joint of the antennae, the insertion of the arista in the vicinity 

 of its basis, the laterally compressed abdomen of the males, the not 

 elongated metathorax, and the wings being more or less narrowed towards 

 the basis ; they have the greatest analogy to the species of Anepsius, the 

 first joint of the antennae of which, however, is clothed with hair; from 

 Campsicnemus they are distinguished by the not elongated metathorax, 

 by the abdomen, which is longer and not flattened from above, and by the 

 face, which is narrowed towards the bottom ; the end of the fourth longi- 

 tudinal vein converges somewhat, in the European species, towards the 

 third longitudinal vein ; in the North American species it is parallel with 

 it or almost so. (The want of the small transverse vein, and of the sixth 

 longitudinal vein, which occurs in a number of the impressions of Tab. 

 VI, are merely mistakes of the engraver, which were discovered too late 

 for correction.) Campsicnemus is distinguished by its face attenuated 

 upwards, the distinctly elongated metathorax, and the short and, in both 

 nexes, much flattened abdomen ; the third joint of the antennae is small, or 

 rather small, and in most of the species somewhat pointed ; the dorsal 

 arista is inserted in rather close proximity to the basis ; the fourth longi- 

 tudinal vein is always parallel to the third, and runs before its middle over 

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