CHARLES W. HOOKER, 137 



in Eremotylus and twice bent in Allocamptus. As the first 



revision this must be accepted (International Code, Article 28) 



if the two genera are retained, Kriechbaumer and Schmie- 



deknecht also retain the two genera* with practically the 



same generic differences, which are : 



Metathorax with only one weak transverse carina ; base of radius 



doubly bent, mesosternum granularly punctured, nervulus 



and nervellus plainly postf ureal. 



Allocamptus Thoms. {Cymatoneura Kriechb.). 

 Metathorax with an anterior carina strongly raised in the middle, more 

 or less strongly reticulate ; base of radius once bent. 



Eremotylus Forster {Camptoneura Kriechb,)." 



Examinations made of a long series of specimens show 

 that none of these supposedly generic characters are constant 

 in the American species which I have seen. The anterior 

 metathoracic carina varies in shape and size throughout, as 

 does the amount of the reticulation of the metathorax. The 

 amount of flexure of the base of the radius shows similar 

 variation, and a good series of E. macrurus and E. arctic 

 furnishes specimens which show a complete gradation from 

 the once-bent to the twice-bent condition. In E. texanus 

 Ashm, we find a similar variation, while macrurus and angn- 

 latus and flavofuscus with its subspecies radialis show varia- 

 tion along another line, the radius being angularly broken. 

 Specimens of E. macrurus, E. arctice, etc., show that differ- 

 ences in punctation of the mesosternum appear equally in all 

 the species. The nervulus is interstitial or pref ureal — some- 

 times well prefurcal — and the nervellus is broken well below 

 the middle, in all American specimens of this group which I 

 have seen, not as Schmiedeknecht says, "plainly antefurcal 

 in Allocamptus.'''' These differences described by Schmiede- 

 knecht and others may be fixed in the European species, 

 allowing a division into two genera, but they certainly are 

 not in the American forms and are therefore of only specific 

 value. There is undoubtedly variation along the lines of 

 radius once-bent and twice-bent as shown in macrurus and 



* Kriechbaumer proposes the name Cymatoneura to take the place 

 of the generic name Allocamptus Thoms., which was preoccupied by 

 Allocamptus Forster. 



TRANS. AM. ENT. SCO. , XXXVIII. (18) 



