270 MB. a. beook's eevision of the 



A Eevision of the Grenus Entomohrya, Eond. {Degeeria, Nic). 

 By Geoege Beook, E.L.S. 



[Eead May 3, 1883.] 



(Plates X. & XI.) 



M. BoFELET, in his paper before the Eoyal Society of Lille, in 

 1839, divided the Podwai into five genera — two with scales and 

 three without. Of the latter the genns Isotoma was charac- 

 terized as follows : — " Corps non garni d'ecailles, plus ou moins 

 vein ; antennes courtes, de quatre articles, a pen pres egaux " 

 (p. 399). It may be here remarked that, from the above descrip- 

 tion, it is clear that Bourlet's name of Isotoma had reference to 

 the segments of the antennae being equal ; and this is borne out by 

 the fact that Bourlet regarded the form and number of seg- 

 ments of the antennae of the Fodurce as forming good generic 

 characters. At the present time, however, unless one had access 

 to Bourlet's papers, one would expect the name Isotoma to refer 

 to the four subequal abdominal segments, as the form of the 

 antennse is no longer characteristic. 



In 1842 Nicolet published a paper (Eoy. Soc. Helv.), in which 

 he divided the species included in Bourlet's Isotoma into two 

 genera : — 



Desoria, in which the first four abdominal segments are sub- 

 equal. 



Degeeria, in which the fourth abdominal segment is at least as 

 long as the three preceding taken together. 



The name Desoria has had to give way to the older one of Isotoma, 

 and hitherto Degeeria has stood as a good genus. The name, 

 however, is unfortunate, as it was already occupied for another 

 genus of insects. Meigen in 1838 (Syst. Beschr. eur. Zweifl.) gave 

 the name Degeeria to a parasitic genus of Diptera, which now 

 forms a large and important genus of the order. Curiously enough, 

 Nicolet's genus is the only one mentioned in Agassiz's ' Nomen- 

 clator.' If the two genera were very wide apart so that there 

 could be no risk of confounding them, perhaps it would do no 

 harm to retain Nicolet's name. E-ondani (Dipterolog. Ital. Prodr, 

 vol. iv.), seeing this difliculty, suggested the name Entomohrya 

 instead of Nicolet's Degeeria ; and although the name is not a 

 very suitable one, it will be better to accejDt this than confuse 



