OBSERVATIONS. 



Two genera of dipterous insects have already 

 been constituted, in which the eyes are pedun- 

 culated, or situated at the extremity of elongated, 

 immovable processes of the head: these are 

 Diopsis of Linneus, and Achias of Fabricius. 

 The present genus differs from the former, 

 however, in not having the antennae situated on 

 the puduncles of the eyes, but on the front, as 

 in AcHiAS. It agrees w4th the former in the 

 terminal origin of the seta of the antennae, and 

 in the rotundity of the third joint of those 

 organs, as well as in the armature of the scutel 

 and lateral part of the trunk. In the little 

 known genus Achias, we are informed the 

 terminal joint of the antennae is elongated, 

 cylindrical, and setigerous at base, and that its 

 scutel is emarginate. It is therefore obvious, 

 that the genus under consideration must be 

 placed between Diopsis and Achias ; and that 

 notwithstanding the brevity of the processes of 

 the head, and the frontal origin of the antennae, 

 it appears to be more intimately allied to the 

 preceding. 



PLATE 52. 



