HOUSE FLIES AND BLUEBOTTLES 



2It 



hats, under the edge of carpets, &c. A window-casing, 

 solidly nailed on the wall, when removed, showed a solid 

 line of them from top to bottom. They like new 

 houses, but are also found swarming in old unused 

 buildings. But most of all they like a clean dark 

 chamber, seldom used, and, if not disturbed, form in 

 large clusters about the ceilings. Under buildings, 

 between earth and floor, they are often found in in- 

 credible numbers." 



Flies are subject to the persecutions of animal as well 

 as vegetable parasites, some of which attack them 

 externally and some internally. The chief external one 

 is a reddish kind of mite (Fig. 69). These creatures 

 may be found, principally 

 during the summer months, 

 on different parts of the 

 bodies of the flies, especially 

 on the under surface ; here, 

 in the neighbourhood of the 

 attachments of the legs, and 

 at the junctions of the body 

 segments, there are plenty 

 of places the joints of the 

 armour, as it were where 

 the skin is thin enough for 

 the mites to pierce with 

 their snouts. They show a 

 good deal of enterprise in 

 endeavouring to secure the 

 best places no easy matter 

 when there are a good num- 

 ber of them and when one has plunged its proboscis 

 into the flesh, it adheres most tenaciously, and its body 

 may be lifted up and pushed from side to side without 



FlQ. 69. Mite Parasite on Fly. 

 Taken from body of Pollenia 

 rudis. 



