108 
DIPTERA.. 
By nibbing paraffin over bis hands, neck, and face, 
Mr. Wood subsequently found himself safe from their 
attacks. 
The insects belonging to the Xylophagidce are ex¬ 
tremely rare and few ; the lame, as the name of the 
family implies, live in decayed wood. 
The Asilidw are the most powerful and generally the 
largest of the Diptera; they are carnivorous in their 
habits, feeding on other insects, and may sometimes be 
seen flying away with some unlucky bee or beetle in the 
mouth. Asilus crabroniformis (Plate IV., Fig. 11), is 
a large conspicuous insect, marked yellow and black, 
which gives it a wasp-like appearance; it is generally 
distributed. 
The flies of the family Leptidce may be often seen in 
hedges and woods; one very common species may be 
found upon the trunks of trees or posts near the 
water-side ; this is the Leptis scolopacea , the Oak-fly of 
the angler, sometimes called the Downhill-fly or Down- 
looker, from the habit the insect has of immediately 
turning its head downwards after settling on a tree. 
It is known to the fly-fisherman also by the name of 
the Woodcock-fly, the colour bearing some resemblance 
to that of this bird. The small feathers of the wood¬ 
cock or grouse are used in making the artificial hackle- 
flies. A fly of the same family, and of somewhat similar 
appearance, is the Atlierix Ibis ; I have seen these flies 
congregating in thousands on rails across rivers, brood¬ 
ing over a mass of eggs, which they attach to boughs or 
other objects overhanging streams. The flies die soon 
after laying their eggs, others come and do the same, 
till large masses are formed as large as a man’s fist. 
