THE HONEY-GUIDES 73 



more as large as its beak, and five bee grubs. After it finished eating, 

 it wiped its bill lengthwise on a branch and then flew off and perched 

 on another twig of the same tree and began calling its repetitive 

 vic-tor notes. 



Credit for suspecting that wax may be a food source to the honey- 

 guides should be given to Moreau (in Sclater and Moreau, 1932, 

 p. 667), who noted that the birds of this family are largely dependent 

 on "wax-producing insects, and swallow quantities of wax with their 

 food; yet the insects providing the staple food of the different genera 

 of the Indicatoridae belong to different orders, and are of an utterly 

 different way of life. It leads one to suspect that wax itself may be 

 utilized by the birds, although it is a material generally regarded 

 as indigestible by animals." 



In order to determine whether the honey-guide can and does digest 

 any of the wax it eats, samples of dried comb were saved; later, a 

 bird (7. indicator) was shot and its entire digestive tract quickly dried 

 and forwarded to me through the cooperation of D. C. H. Plowes. 

 Subsequent chemical analysis of a piece of the comb, of wax from the 

 gizzard, from the upper part of the small intestine, and from the 

 lower part of the large intestine were made by Dr. A. H. Warth. 

 The melting points and the softening points of the wax were deter- 

 mined with a Fisher-Johns apparatus, an electrical microapparatus 

 consisting of a cylindrical aluminum block in the bottom of which is 

 a spiral hole. This spiral hole contains the heating element, which is 

 shielded by aluminium oxide. "The bulb of a thermometer lies 

 horizontally in a hole bored near the surface of the block. The 

 whole block is surrounded by a bronze ring . . . The substance 

 being tested is placed . . . between cover glasses on an aluminum 

 stage which is lilvewise electrically heated. A magnifier above the 

 sample makes it possible to see the actual point at which melting 

 takes place. The side armored thermometer is graduated from 20 to 

 300°." (Warth, 1947, p. 334.) 



The results of these tests are tabulated below. 



Temperature in degrees 



Softening Running Fully melted 



Source of wax C. F. C. F. C. F. 



Dried comb 52 126 64 147 67. 5 154 



Gizzard 54 129 65 149 68 154 



Upper part of small intes- 

 tine 130 266 160 320 170 338 



Lower part of large intes- 

 tine 110 230 119 246 150 302 



It will be seen that the wax from the gizzard corresponds closely to 

 that from the dried wdd bee comb and is, therefore, interpretable as 



