54 FOREST FLIES. 



many hairs placed along the fine bristle being observable, only their 

 lower portions were noticeable, the bristle thus having the appearance 

 of being beset by fine spikes. The terminal extremity was not 

 pointed, but ended in about five spines, or moderately sharp spine-like 

 tubercles. 



In the course of my observations on the method of movement of 

 Forest Flies and their power of adhesion to upright surfaces, such as 

 the sides of a cardboard box, I found that (when observed by hand- 

 magnifiers of two-inch power) they did not appear to make any use at 

 all of their strong curved claws to help them up the ascent. The 

 claws were thrown up and somewhat back, so as to be clear from any 

 attachment at all, and the fly progressed upwards to all appearance 

 holding by the thick basal portion of the claws only. On investigation 

 I found (at this spot) an appendage, invisible without high magnifying 

 power, which does not appear to have been previously observed, and 

 which, when displayed, proved to be a thin flat membrane, down the 

 centre of which ran a vein, or tube, curving from each side of which 

 were a series of channels, or ridges, running to the edge of the 

 membrane, about twenty in number on each side. This formed a thin 

 flat plume-like flap, at the base of which was a bulb-like formation, 

 thickly covered with hairs.* The general appearance of this mem- 

 brane bears (at first glance under a high magnifying power) a great 

 resemblance to the flexible lobes known as hibella, which form the 

 terminal portion of the proboscis of the Blue-bottle Fly.f In these 

 labellae the side tubes (which it is noted by Mr. Butler are called 

 pseudo-trachecE on account of their superficial resemblance to tracheal 

 tubes) difler somewhat in disposition from those in the apparatus in 

 the Forest Fly's foot, as in this case the series on each side starts from 

 the central vein or tube, — in the proboscis of the fly each side series 

 starts from a separate longitudinal tube or vein ; but beyond the 

 external appearance, which is given in my two plates referred to in 

 the note, I am not aware of the structure of this part of the foot 

 apparatus of H. equina having been entered on. 



The HippoboscidcE, to which family the Forest Fly belongs, are 

 distinguishable by not existing actively, except in imago state — that 

 is, perfect or fly state. The egg is hatched, and the maggot, or larva, 

 feeds and is nourished up to maturity in the abdomen of the female 

 fly, and when fully developed is deposited, and the change to pupal 

 condition (in all ordinary external characteristics) takes place so 



* In my Nineteenth Annual Report two plates are given, in which the foot of 

 H. equina, with the claws and the various appendages, will be found magnified ; 

 one of these plates is repeated now as frontispiece. 



t See figures, much magnified, given in plate ii. of ' Our Household Insects,' by 

 Edw. A. Bucler, B.A., B.Sc. 



