250 HALF-AN-HOUR 



morsitans^ whence, no doubt, this came. The large size of the 

 trachese is noteworthy, and I think, so far as my examination 

 extended, the fibre appeared to cease in the tubes much earUer 

 than usual. 



B. T. Lowne speaks of its being visible in the Blow- Fly {Miisca 

 voinitorid) in tubes down to the calibre of i — io,oooth of an inch 

 {A?iat. and Physiology of Blow-Fly^ p. 26). Mr. Lubbock has 

 some important remarks on " Tracheal Tubes " in the Linn. 

 Titans, of some 10 or 12 years ago. 



Lipeurus baculus (Plate 28, Figs, i — 5). — So far as I have had 

 the opportunity of ascertaining, I believe that all the bird pediculi 

 feed on the feathers^ with which their stomachs may at times be 

 found to be crammed. 



Reference to H. Denny's " Monographia Anopliirorum Brit- 

 ajinice " would teach at once that the present specimen is a male. 

 It will be advantageous to compare the hooked antennae of this 

 species with other examples found in bird-lice, and these with cor- 

 responding structures in spiders and many Crustacea. Feet are 

 not well shown in the slide. Spiracles exceedingly small. I think 

 there are twelve on each side. Note the mouth-organs. The true 

 homologues of them offer an interesting problem for solution. 

 The long terminal hairs have undoubtedly important functions to 

 discharge of a sensory nature, and may be well compared with the 

 tails of crickets and other orthoptera. I think Shakespeare has 

 an interesting allusion to the important uses of the anal setae in 

 the cricket, but have not time to turn it up just now. 



The bird-lice have not such " sharp claws for adhering to the 

 skin." "Their mode of progression is rather singular as well as 

 rapid. They slide, as it were, sideways, extremely quick, from one 

 side of a fibre of the feather to the other, and move equally w^U 

 in a forward or retrograde direction." (Note here the beautiful 

 adaptation of the limbs for such use), " which, together with their 

 flat, polished bodies, renders them extremely difficult to catch or 

 hold." — (Mon. Anop. Brit., p. 166, sub. L. Poly trapezius.) 



This description is highly graphic. The Hce of the common 

 fowl ( Menopon pallidum) are sometimes very numerous, and then 

 become a great plague to those who have to pluck the birds, irri- 

 tating excessively by running over the skin, though in a few hours 

 they die for want of proper food. 



Denny says of L. Baculus : — " I find this species very common 

 on all varieties of pigeons, and living in society with Nirnuis 

 clavifonnis and Goniocotes covipar. Few birds, indeed, are so 

 infested with parasites as the Columbidce-. Besides four species of 

 lice, I have found a large Ixodes, a small Acarus, and the Pulex 

 Columbcs; and the Rev. L. Jenyns has detected a bug, Cimex 



