170 



SCIENCE 



[N. S. Vol. XLIII. No. 1101 



also to be largely used, at any rate by the males, 

 for purposes of display. Where the powers uf 

 luminosity are largely developed in this sex the 

 emission of the light is usually of an intermittent 

 flashing type. It has been noticed in various par^s 

 of the world that these flashing males tend to con- 

 gregate in large companies, and that all the indi- 

 viduals of one of these gatherings will flash in con- 

 cert. All the fireflies around one tree or group of 

 trees, for instance, will flash together, while those 

 around a neighboring tree will be pulsating to a 

 different time. This feature has been observed of 

 a European species of Luciola (though Mr. Main 

 and myself were unable to detect anything of the 

 sort with L. italica at Lugano), of an Indian 

 lampyrid genus not stated, and of the genus 

 Aspidosoma in South America. The American 

 species of Flwtinus and Fhoturis do not seem to 

 possess the habit. 



The exact reason of this flashing in concert, or 

 the method by which it is brought about, have not 

 been ascertained. It has been suggested that the 

 light is not really intermittent in character, but 

 merely appears so owing to its being alternately 

 masked and exhibited by movements of the crea- 

 ture's body, and that a slight puff of wind might 

 perhaps affect all the members of a company and 

 cause them all to conceal their lights at once. 

 Though this explanation of the intermittent char- 

 acter of the light applies well enough to Pyroplwrus, 

 an insect we shall shortly consider, it is certainly 

 not applicable to these Lampyridffi. It is true the 

 light is not absolutely extinguished between the 

 flashes, but it is so diminished as to become prac- 

 tically dark; moreover the flashing in unison is too 

 regular to be caused by chance puffs of wind. A 

 more probable explanation of the phenomenon is 

 that each flash exhausts the battery, as it were, 

 and a period of recuperation is required before 

 another flash can be emitted. It is then conceiv- 

 able that the flash of a leader might act as a stim- 

 ulus to the discharge of their flashes by the other 

 members of the group, and so bring about the 

 flashing concert by the whole company. 



Edwabd S. Morse 



polyradiate cestodes 

 In the last number of the Journal of Para- 

 sitology, VoL 2, No. 1, p. 7, W. D. Foster, of 

 the Bureau of Animal Industry, U. S. Depart- 

 ment of Agriculture, gives an interesting sum- 

 mary of the cases of polyradiate cestodes and 

 describes an adult triradiate eestode of the 



species Twnia piriformis " found in a mass of 

 tapeworms expelled by an imported collie dog." 

 He states that " no case of an adult triradiate 

 eestode of this species has yet been published." 

 It is to be regretted that Foster did not inves- 

 tigate more thoroughly the literature on the 

 polyradiate cestodes before publishing his 

 article. 



In Science, 1910, ]Sr. S., Vol. 31, p. 837, in 

 an article " Some ISTew Cases of Trihedral 

 Tfenia," we published a brief description of 

 two new species of polyradiate cestodes based 

 on the study of four perfect and entire speci- 

 mens of Tcenia serraia =■ Twnia pisiformis 

 and three perfect specimens of Twnia serialis 

 which were secured from four dogs picked up 

 on the streets of Lincoln. 



Foster bases his description on a " number 

 of chains of triradiate proglottids, the longest 

 piece being 23 em. representing the anterior 

 half of the worm, except the head." From the 

 study of our specimens we question the valid- 

 ity of a specific diagnosis of Twnia pisiformis 

 from proglottids alone, without verification 

 from the scolex. 



He states that "the identification of the 

 species was verified by feeding experiments on 

 a rabbit " and that " although shipped in a 

 solution of formalin of unknown strength, and 

 kept in a 2 per cent, solution of formalin for 

 one week after it was received, it was deter- 

 mined to use some of the material for feeding 

 experiments." Foster states that he recovered 

 seven " perfectly normal larvse " of Twnia pisi- 

 formis from the omentum and body cavity of 

 a rabbit reared and kept in captivity, thirteen 

 months after feeding with two of the proglot- 

 tids of the triradiate Twnia pisiformis which 

 had been preserved and kept in formalin. It 

 seems to us that the reliability of the results of 

 these feeding experiments is open to serious 

 question, first in the use of material preserved 

 in formalin of uncertain strength and kept in 

 a 2 per cent, solution for one week after it was 

 received and second in the uncertainty as to 

 the previous natural infection of the rabbit 

 used, for we have repeatedly found our rabbits, 

 born and reared in captivity, heavily infected 

 with Oysticercus pisiformis. 



