C-IO INSECTS AT HOjIE. 



which it travels with a rapidity that seems scarcely possible in 

 such a locality. 



I never saw a sloth on a level or smooth surface, but it is 

 well-known that the long and curved claws which are so useful 

 among the branches, are absolutely impediments when the 

 creature is on flat and hard ground on which its claws have no 

 hold. Similarly, I find that whereas the common Flies can 

 move about actively enough on glass, even though it be 

 upright, the Sheep-tick is quite at a loss when placed on a 

 plate or any similarly smooth substance. Under such circum- 

 stances it moves its legs with great rapidity, but does not suc- 

 ceed in making much progress, and the unwonted effect of its 

 exertions seems to throw it into quite a fever of fright and 

 anxiety. 



This is one of the wingless species. It is so completely 

 without wings that even the practised eye of the entomologist, 

 aided by the microscope, can hardly detect the undeveloped 

 riuliments of these organs. The insect, indeed, seems to be 

 nothing but legs and abdomen, the latter being nearly flat and 

 round, this shape being intended to serve a purpose which will 

 presently be described. 



On Woodcut LXXVI. Fig. 2 is given a figure of the Finch 

 Fly ( Omit ho my ia fHngillaria). 



On the right hand of the Fly, and at Fig. d, is drawn the 

 under part of the head, so as to show the horny projections 

 which have already been mentioned in the description of the 

 Sheep-tick. JMr. Kirby remarks that he has himself suffered 

 from the attacks of one of the Ornithomyias, which would 

 persist in alighting on his head, and driving their beaks into his 

 skin. He succeeded in catching two specimens, and found 

 them to be Ornithomyia avicularia. 



The colour of our present species is ochreous, changing in 

 some lights to green. The head and thorax are shining 

 yellow, mottled with brown, and having a faint line down the 

 middle of the back. The abdomen is dull green and hairy, 

 the legs are bright green, and the claws jet black. The wings 

 are iridescent and smoky. This is the smallest species of its 

 genus, and it is found on various small birds, such as the tit- 

 mouse, the yellow-hammer, and the robin. 



