THE FEEDING OF LICE 9 



If this is not done lice, especially larvae and nymphs, will get 

 between the bottom of the box and the bolting cloth and be 

 destroyed. The edge of the aperture should be smoothed off 

 to prevent cutting the cloth. Inside the box we placed a 

 loosely fitting disc of thin black felt and, above it, a narrow 

 strip of loosely coiled felt (any heavy cloth would do as well). 

 After introducing the lice, bolting cloth is placed across the top 

 of the box, the cover pressed into position, and the free edges of 

 the bolting cloth trimmed with scissors. Finally, as a safe- 

 guard, the union of cover and bottom of box is sealed by wrap- 

 ping with a strip of adhesive plaster. 



(The boxes used by us were made from metal "tin" ointment 

 boxes, 4 cm. in diameter, 1.5 cm. deep. Apertures 2.5 cm. in 

 diameter were cut in the bottom and in the top of the cover. 

 The leather straps (Figs. 2 and 3) used in wearing the boxes 

 were 80 cm. long, in order that the boxes could be worn upon 

 the leg). 



In maintaining stock lice the boxes were worn daily for, at 

 least, two periods of one hour each, separated by at least eight 

 hours. Between feedings, the boxes were carried in waistcoat 

 or trousers pockets for warmth. When it was desired to raise 

 large numbers of lice the boxes were worn continuously. Over- 

 crowding of stock boxes must be prevented by occasional re- 

 moval of excess numbers of lice and the cast off skins (moults). 



In badly soiled boxes the meshes of the bolting cloth may be- 

 come clogged with excreta, a condition which requires trans- 

 ference of the colony to a freshly prepared box. 



No difficulty was experienced in raising and maintaining our 

 stocks of lice in these metal boxes, which have the great ad- 

 vantages of strength, durability, and ease of sterilization. 



5. THE SECTIONING OF LICE 



Our purposes demanded a technic which could be applied on 

 a large scale and yet give the perfect fixation required for the 

 demonstration of delicate micro-organisms in the tissues of lice. 

 The obstacle to all stages in section technic fixation, em- 

 bedding, and cutting is the impervious chitin cuticle. 



