NEW .mali.()PHA(;a. 153 



by a double motion. Tlicy then grasp the feather 

 and by their own nnjlion Imckwaid and by the motion 

 of the body forward on the hind legrf tlie femoro-tiljial 

 angle is again deereased and the leg assumes its former 

 position. The inseets run along on the feathers very 

 easily, generally preferring the shaft. Those exj)eri- 

 mented with wero kept on a few bits of feather on a 

 glass slide. They ran along the shaft of a feather until 

 they came to the end, then backed up a short distance, 

 turned around, and ran back to the other end to go 

 through the same performance there. They generally 

 move with the head forward but ean apparently go 

 backwards or at any lateral angle just as easily; they 

 nearly alway.-^, however, turn around when they wish 

 to reverse the direction of movement. When several 

 were placed on some guinea-pig hairs they appeared to 

 be at no loss at all as to how to get along, and traveled 

 just as well as on the feathers, although perhaps a little 

 slower. Some Pediculids, however, from the guinea- 

 pig, when placed on some feathers, appeared to be 

 somewhat hindered by the network of barbs and bar- 

 bules. The Mallophaga were entirely unable to progress 

 upon the glass slide when they got off of the feathers, 

 but the lice showed no ditticulty at all in this respect; 

 the latter ei>uld also right themselves when placed on 

 their backs while the former eould not. 



11. TuE Alimentary Canai. ank its .Vii'Kndaces. 



Tin All mental' ij Canal. — The alimentary eanal pre- 

 sents two tyi)es of structure. < Mie form is simple, having 

 no special development at any par;, ihe other is com- 

 plicated by a lateral and backward })rolongation of the 

 crop, so that the latter forms a large expanded divertic- 

 ulum of the oesophagus. The lirst form is contined to 



