OF HARTING. 431 



until its wings are fully expanded and fitted for flight. 

 There are few individuals who have not, when wooing 

 " tired nature's soft restorer," been startled into wake- 

 fulness in the silence of night by the piping of the 

 bloodthirsty gnat ; there are fewer still, probably, who 

 could believe in the possibility of even approximately 

 estimating the number of vibrations of its wings in a 

 given time, while it is sounding this note of alarm, 

 yet the solution of this problem has been attempted 

 by natural philosophers. In elementary works on 

 Acoustics we learn that the gravest note audible is 

 produced by about thirty-two, and the sharpest by 

 about fifteen hundred, vibrations in a second. As the 

 piping of the gnat, when compared with the latter, 

 is found to be in unison with it, it follows that this 

 tiny trumpeter vibrates its wings no less than ninety 

 thousand times in a minute, a velocity one would 

 suppose sufficient to throw off the delicate scales with 

 which the wings are fringed. 



The family of Crane-flies is a very extensive one, 

 and contains many genera as well known as the 

 Gnats, to which indeed some of the smaller species 

 bear so strong a resemblance, that they are often 

 mistaken for them, but the structure of the mouth in 

 the majority of them is less perfect than that of 

 Culcx. Chironomus plumosus, remarkable for the 

 feathery character of its antennae, is common enough 

 here, and is gnat-like, both in its form and its 

 economy. Its larvae are those very active blood-red 

 worms so often seen in stagnant water in pools, in 

 uncovered cisterns and water-butts. 



The economy of the Gall-gnats is similar to that of 

 the Gall-flies among the Hymenoptera, the deposition 

 of their eggs within the substance of different species 

 of plants is followed by excrescences, irregular growths, 

 and distortions of the parts attacked, and in these the 

 larvae feed and undergo their transformations. One 

 of the members of this division, Cecidomyia Tritici, is 



