tract from Mr, T.'s letter upon the subject, I have to acknow- 

 ledge my obligations to N. A. Vigors, Esq. — " 1 took this 

 insect two succeeding years (1822 and 1823) early in the 

 month of May along the margin of Lough-bray, a small lake 

 in the county of Wicklow, close to which the military road 

 passes. I have not been able to ascertain the elevation above 

 the level of the sea of this lake ; but I think I do not err much 

 in saying that it may be about 1200 feet. The rocks sur- 

 rounding it are primary (granite), and the surface is entirely a 

 black peat in many places several feet in depth ; the plants 

 almost exclusively prevailing are our Common Heath [Erica 

 vulgaris), Vacci?iium Mi/rtilltis, and a variety of Mosses occur- 

 ring in such situations ; there are also a few stunted Willows, 

 Mountain Ash, and Birch. I have seen few places of the 

 same elevation so perfectly alpine : at the period of my visits 

 the insect occurred in great numbers, almost like some of the 

 Ephemeridce." 



Linnaeus finding^this species in Lapland gave it the specific 

 name of horealis : it has since been taken in Bavaria and 

 near Aix-la-Chapelle, upon the flowers of the willow: Fa- 

 bricius says that in Sweden it is seen in clear and serene 

 evenings dancing in the air. 



Mr. Kirby, in his entertaining Introduction to Entomology, 

 compares the rostrum of the Emjndce and Asili with the beak 

 of a bird, and some of their wings with the fins of a fish, of 

 which there cannot be better examples perhaps than the head 

 of E. tessellata, and the wings of the female E. borealis figured 

 in the plate; from the peculiar form of which, Mr. Stephens is 

 disposed to consider the latter a distmct genus, in which 

 opinion he is supported by the difference of the antennae from 

 the generic type. Meigen in his last volume, published in 

 1822, enumerates 47 European species of Empis ; in this 

 country there are only about 12 known. 



The female Taxzis baccata (Common Yew-tree), found in 

 mountainous woods, is figured in the plate. 



