290 Mr. Westwood on Diopsis, 



Of the history of this genus few words will suffice. Linnaeus in 1775 esta- 

 blished the genus, and described one species only, D. ichneumonea, which name 

 Fabricius adopted ; but it would appear that the latter confounded, under that 

 name, two species distinct from each other as well as from the original species. 

 Illiger added another species, D. nigra ; Donovan also described another from 

 the East Indies under the name of D. ichneumonea ; Say added a North Ame- 

 rican species, D. brevicornis ; and Dalman, three new African species, noticing 

 also Linnasus's and lUiger's species, and the confusion in the specific description 

 of Fabricius, but overlooking Donovan's error. Wiedemann followed Dalman, 

 adding another species, D. Dalmanni, and giving the Fabrician species as distinct 

 under the name of D. confiisa, making (together with Say's insect) 8 species ; 

 to which Mr. G. R. Gray has added another in Griffith's Animal Kingdom. In 

 the following pages 18 species, together with 3 doubtful ones, are described*. 



As in Paussus, the geographical range of Diopsis seems confined to the tro- 

 pical climates of the Old World ; the central parts of Africa (to which alone 

 Dabuan thought it restricted), the East Indies and Indian islands producing 

 all the species, except Say's North American one, which scarcely seems to 

 belong to the genus. 



As to the affinities of the genus, Linnaeus, from the existence of its halteres 

 and small proboscis, was convinced that it was a Dipterous insect, although in 

 its spinose thorax it diflTered very much from all the Diptera, approaching 

 Formica, whilst in its long legs, clavate abdomen, and spotted wings it re- 

 sembled the Ichneumons. 



Latreille was very early aware of its affinity with the domestic fly, and he 

 accordingly placed it in the great group Muscidce, in the same division with 

 the genera Sepedon, Tetanocera, Oscinis, Calohata, and Achias {Gen. Crust. S§c., 

 vol. iv.). Fallen, who divided the Muscidce into four subfamilies, placed Z)/- 

 o;>5M amongst the Ortalides, including Sepedon, Tephritis, Sepsis, Micropeza, &c. 

 Dalman, however, from its short rounded antennae, deemed it to belong to Fal- 

 len's Micromyzidw, adding, " Melius forsan ad propriam familiam Diopsis cum 

 Achia amandanda." Wiedemann, however, in his memoir upon Achias, ex- 



* I have not been able to discover in our public libraries a copy of MM. Villars and Capelle's 

 Journal de la Socie'lt de Sante et d'Hisloire Nuturelle de Bordeaux, in the first volume of which (p. 77.), 

 I believe LatreUle published a notice or memoir upon this genus. 



