230 



SCIENCE 



[N. S. Vol. XXXVIII. No. 972 



the department of geography at the Ehode 

 Island Normal School, Providence, R. I. 



At University College, Reading, Mr. S. B. 

 McLaren, assistant lecturer in mathematics at 

 Birmingham Unirersity, has heen appointed 

 professor of mathematics, and Mr. R. C. Mc- 

 Lean lecturer in hotany. 



DISCUSSION AND COBBESPONDENCE 



THE NAME OF THE SHEEP MEASLE TAPEWORM 



CoBBOLD in 1866 described a cysticercus 

 from the muscles of sheep in England and 

 named it Cysticercus ovis. The same species 

 was later described by Maddos (1873) under 

 the name of Cysticercus ovipariens. Other 

 authors hare considered the parasite to be 

 either Cysticercus celluloses, the intermediate 

 stage of Tcenia solium, in an unusual host, or 

 Cysticercus tenuicollis, the intermediate stage 

 of Tcenia marginata or hydatigena, in an un- 

 usual location (muscles instead of serous mem- 

 branes). Recent investigations by the present 

 writer have proved that the parasite in ques- 

 tion is neither G. cellulosce nor C. tenuicollis 

 but the intermediate stage of a distinct species 

 of dog tapeworm. The correct name of this 

 tapeworm would, therefore, seem to be Tcenia 

 ovis (Cobbold, 1866). B. H. Ransom 



BiTKEAU OF Animal Industry, 

 Washington, D. C. 



note on the orientation of bombilius 



TO LIGHT 



While on the hills east of Berkeley, Cal., I 

 observed, among numerous insects visiting the 

 flowers of certain shrubs, that there were sev- 

 eral flies which kept hovering for a consider- 

 able time in almost exactly the same position. 

 The flies proved to belong to a species of 

 BomhiliUs. The instinct of hovering is not 

 rare among the Diptera, especially the Syr- 

 phidse, but what especially attracted attention 

 was the accurate orientation of the hovering 

 insects to the rays of light. In all the numer- 

 ous cases observed the flies had their backs 

 turned toward the sun, and in all cases the 

 hovering occurred in the direct sunlight. 

 Whenever a shadow was thrown upon a hov- 

 ering fly it immediately darted elsewhere. 



Occasionally the flies alighted on the ground, 

 when they rested with the back exposed to the 

 sun as before. When a shadow was thrown 

 on them they would soon fly to a sunnier spot. 

 In a few cases I caused them to orient ob- 

 liquely to the sun's rays by slowly moving an 

 object so that its shadow was thrown on only 

 half the body of the insect; the body would 

 then be turned so as to face more nearly the 

 center of the shaded region. In basking in 

 sunny spots and in orienting negatively to 

 the rays of light the behavior of Bonibilius 

 resembles that of the mourning-cloak and 

 other butterflies described by Eadl and 

 Parker. Like the mourning-cloak, Bombilius 

 under ordinary circumstances is positively 

 phototactic. It will fly or walk toward the 

 light as so many other Diptera do, but when 

 resting on the ground in the sunshine or 

 hovering in the air it assumes a negative 

 orientation. It is of interest to find such 

 striking similarities of behavior in two dis- 

 tantly related orders of insects. 



When resting on the ground or hovering, 

 Bombilius often darts quickly at passing in- 

 sects. It is not very discriminating as to the 

 objects of its approach and was several times 

 seen to follow after honey-bees and twice after 

 yellow-jackets. When the fly meets a mem- 

 ber of its own species the two often spin 

 around in a rapid whirl, but when a mistake 

 is made the pursuit is immediately aban- 

 doned. I have caused Bomhilius as well as 

 other species of hovering flies to dart after 

 small pebbles that were tossed in the air. 

 This behavior is probably associated with the 

 instinct of mating, since it occurs in non- 

 predatory as well as predatory species. 



S. J. Holmes 



SCIENTIFIC BOOKS 



Handworterhuch der Naturwissenschaften. 

 Herausgegeben von E. Korschelt, Zoologie; 

 G. LiNCK, Mineralogie u. Geologic; F. Olt- 

 MANNS, Botanih; K. Schaum, Chemie; H. 

 Th. Simon, Physik; M. Verworn, Physiol- 

 ogic, und E. Teichmann, Hauptredahtion. 

 Jena, Verlag von Gustav Fischer. 1912. 



