102 Kansas Academy of Science. 



fully selected beef scraps. Flies taken from nature were placed in small, 

 lantern globe, cages, where they were given living embryos from fowl 

 cestodes and kept alive as long as possible, in order to afford time for 

 the development of larval tapeworms (cysticercoids) in the bodies of the 

 flies. 



By giving to the caged flies small amounts of whole sweet milk daily, 

 fairly large numbers of them were kept alive for two or three weeks 

 after they were fed the tapeworm onchospheres. Upon the death of these 

 flies, they were either preserved for sectioning, or given to young chickens 

 reared in the fly-proof fleld cage. In this way several hundred house 

 flies were fed, a few at a time, to twelve chickens. 



In the fowls examined to date, nine cestodes have been found, two 

 from chick No. 165 being sexually mature. Control fowls from the same 

 broods kept with the experimental chickens in no case yielded a single 

 parasitic worm. (Control chicks have been kept constantly in this fly- 

 proof and worm-proof fleld cage for four years, and in no instance has 

 a control chick been infected with a helminth). That the two mature 

 tapeworms from chick No. 165 are apparently Davainea cesticillus, is 

 seen from the following diagnosis: Length, 79 to 90 mm. Maximum 

 width, 1.6 to 2.3 mm. Head cylindrical, 0.5 to 0.6 mm. wide and 0.3 to 

 0.4 mm. long. Suckers unarmed, about 0.1 mm. in diameter. Rostellum 

 broad and hemispherical, 0.29 mm. wide, armed with approximately 200 

 very unstable hooks. Hooks 8 to 9 microns long, with long ventral root 

 and short dorsal root. Neck very short, followed by proglottids equal 

 to or greater in width than the head. Anterior proglottids 3 to 6 times 

 as broad as long; the following increase in size until they become equal 

 in length and breadth and finally longer than broad; borders overlapping. 

 Vagina and cirrus pouch pass on the dorsal side of the two excretory 

 canals and nerve. 



Male Reproductive Organs: Testes, 20 in number in the posterior 

 portion of the proglottid. Ves deferens coiled before entering the base 

 of the cirrus pouch, also coiled within the latter. Cirrus pouch ellipsoidal, 

 139 to 164 microns long by 65 to 82 microns wide. Cirrus when pro- 

 tracted, 131 microns long and 13 microns in diameter, armed with minute 

 spines, and with a bulbous enlargement 21 microns in diameter at its 

 base, where it becomes continuous vnth the cirrus pouch. 



Female Reproductive Organs: Vagina enlarged before reaching the 

 median line into a small seminal receptacle. Ovary occupies the middle 

 field in front of the testes. Yolk gland and shell gland posterior to the 

 ovary, ventral and dorsal, respectively, in relative position. Uterus at 

 first in front of the ovary; gradually increasing in size, it finally occupies 

 most of the segment, extending laterally to the excretory canals. In 

 the oldest proglottids it becomes divided into compartments or capsules, 

 each containing a single egg. Embryo, 35 by 31 microns in diameter, 

 with a very thin membrane closely adherent to its surface. Embryo 

 further enveloped by a thicker, smooth membrane, oval in shape, 42 to 36 

 microns in diameter. Latter surrounded by a thin, wrinkled membrane 

 about 66 to 61 microns in diameter. Egg surrounded by a capsule com- 

 posed of an outer and inner membrane. 



