Dr. Leach, who investigated the species with great attention 

 in the 2nd vol. of the " Werneriaii Transactions," subsequently 

 constituted them as an Order, the propriety of which cannot 

 be doubted, when we consider that these Insects are very dif- 

 ferent to the Diptera both in structure and economy. 



The genus that I have proposed appears to connect Orni- 

 thomyia and Melophagus: to the former it is allied by its wings, 

 the nerves of which however are very different ; and to the 

 latter by its head and antennae. It will be seen that my 

 ideas regardinff the mouth differ from those of other authors ; 

 but as an universal harmony reigns through Nature, I have 

 little doubt but analogous parts to those of the Diptera, vary- 

 ing in their modifications, will be found to bear me out in my 

 observations. The proboscis contahis a labrum, tongue, and 

 a corneous instead of a fleshy lip ; the mentum is veiy large 

 (protecting and concealing two-thirds of the proboscis), with 

 2 valves projecting behind, which I imagine to be maxillae : 

 Latreille suspects they may be palpi, and they have been con- 

 sidered by some authors as mandibles ; but I know of no in- 

 stance in which palpi are rigid and solid ; and where mandibles 

 are developed in the Diptera, they are lancet-shaped, to enable 

 the Insect more effectually to inflict a wound to obtain nourish- 

 ment; whereas in the Omoptera they are not only obtuse, but 

 furnished with strong bristles, which would render them very 

 unfit for such purposes. 



Quadrupeds and birds are the habitations of these Insects, 

 upon whose blood they subsist, and amongst whose wool and 

 feathers many of them secrete themselves so effectually, that 

 it is almost impossible to detect them until some time after 

 the death of the animal ; when the blood becomes cold, they 

 may be seen running in every direction. The unique and 

 nondescript species figured, was taken from off the clothes of 

 Mr. J. Chant, in the New Forest, about the middle of Sep- 

 tember 1822, by Mr. Samouelle, whose "Introduction to the 

 Knowledge of British Insects " has contributed so much to- 

 wards the advancement of Entomology in this country, it 

 having been rendered more generally useful by being written 

 in our own language. 



Caucalis Anthriscus (Hedge Hen's-foot, or Red Hedge- 

 parsley,) accompanies the Insect in the plate. 



