1 46 INTRODUCTION TO ZOOLOGT. 



tumours known among the 

 country people by the name 

 of "wTirbles;" -while one de- 

 voted to the horse fixes them 

 on the parts most liable to be 

 licked by the animal. They 

 are thus taken into the stomach, 

 Fig. 136. Fig. 137. and there they remain at a 



CEsTEus. Labva. temperature of one hundred 



degrees, until they attain their fall size, as the larvae so well 

 known by the name of "bots" (Fig. 137). 



But it would be unjust to allow the reader to leave the 

 Dipterous insects without bringing some of the tribes before 

 him in their hours of enjoyment. Eveiy person is familiar 

 with the appearance of that large-winged, long-bodied insect, 

 known as the " Harry Long Legs ;" the largest species we 

 have of the Tipulidce. The members of this family and thoso 

 which are spoken of as " Mdges" {CulicidoB) have long been 

 noted for then- aerial dances. Every one has observed how 

 they come forth in the sunshine, how they sometimes keep 

 pace with the traveller as he journeys along,* and how even 

 in winter they occasionally present themselves in multitudes. 

 Some instances are recorded of theij appearing in such num- 

 bers as to excite surpiise, and even alarm. Thus, in Phil. 

 Trans. 1767, it is stated that in 1736 the common Gnat 

 (jCulex pipiens) rose in the an- from Salisbury Cathedral in 

 columns so resembling smoke, that many people thought the 

 cathedral was on fire. In Norwich, in 1813, a similar alarm 

 was created. At Oxford, in 1766, "a little before sunset, 

 six columns of them were observed to ascend from the boughs 

 of an apple-tree, some in a perpendicular, and others in an 

 oblique direction, to the height of fifty or sixty feet." 



For some successive evenings towai'ds the middle of June, 

 1 842, a phenomenon similar to that last mentioned was ob- 

 served by us in the vicmity of Belfast. " The msects appeared 

 in columns above the trees, the shade of colour varying according 



* This circumstance has been thus noticed by Wordsworth : — 



" Across a bare, wide common I was toiling. 

 With languid feet, which by the slippery ground 

 Were baffled ; nor could tny weak arm disperse 

 The hosts of insects gathering round my face. 

 And ever with me as I paced along." — Tbe Exccusioir. 



