344 THE AMERICAN MONTHLY [Nov., 



glass rod into the SBSophagus. We then see (1) the aorta, 

 , . . .against the cartilaginous extremities of the posterior 

 horns of the hyoid bone ; (2). . . .muscular fibres extend- 

 ing from these horns to the occipital region ;. . . .the low- 

 est of the muscular bundles is the satillite of the pneu- 

 mogastric which extends along its lower border; ... .a 

 nerve extended on a match is placed in 1 per cent osmic 

 acid for 24 hours. Wash for 12 hours, harden in alcohol 

 and gum; section and stain in picro-carmine for 12 

 hours, wash, mount in water which is to be replaced by 

 glycerine. 



To be continued. 



Keys to the Genera of Pediculidae and Mallophagidae. 



By HERBERT OSBORN, 



AMES, IOWA. 



The following tables which are in part adapted from 

 the tables given in Piagets Les Pediculines and other 

 works will enable one to determine the genus of the 

 parasitic insects infesting birds and animals. 



HEMIPTERA. 



SUB ORDER PARASITA. 

 PEDICULIDiT:. 



Wiugless suctorial insects with clasping tarsi Parasitic upon Mammalia. 



KEY TO GENERA. 



A Thorax wider than abdomen. Body wider than long. Abdomen 



with 6 apparent segments. Phthirius 



AA Thorax narrower than abdomen. Body longer than wide, 



a Al)domen with 7-8 segments (on Primates). 



b Antennae five jointed on (Homo). Pediculus 



bb Antennae three-jointed (on Simiadui). Pedicinus 



aa Al>donien with 8-9 segments (on lower Mammalia). 

 1) Antennae^five-jointed. 



r Head normal, antennae slender. Haematopinus 



cc Head pioduced, tubular in front, antennae enlarged in 



middle. Infesting elephant. Hueinatomycus,* 



bb Antennae four-jointed Echinophthiriun* 



i 



