June 25, 1920] 



SCIENCE 



643 



is it most efficient so far as the radiation, (being all 

 light) it produces is concerned hut also most eco- 

 nomical so far as its chemical processes are con- 

 cerned. The above reactions can be demonstrated 

 in a test tube with a mixture of oxyluciferin, luci- 

 ferase and ammonium sulphide. The ammonium 

 sulphide is probably represented in living cells by 

 reducing enzymes or reductases. If such a test- 

 tube is allowed to stand, oxyluciferin is reduced 

 to luciferin which will luminesce only at the sur- 

 face of the fluid in the test-tube in contact with 

 air. When the tube is agitated so as to dissolve 

 more oxygen of the air the liquid glows through- 

 out. Even a gentle knock or ' ' stimulus '"to the 

 tube is sufiicient to cause enough oxygen to dis- 

 solve to give a momentary flash of light which is 

 strikingly similar to the flash of light given by 

 luminous animals themselves on stimulation. This 

 suggests that when we agitate a luminous animal 

 or when the luminous gland cells of a firefly are 

 stimulated through nerves with the resultant flash 

 of light, in each case the stimulus acts by increas- 

 ing the permeability of the surface layer of the 

 cells to oxygen. This then upsets an equilibrium 

 involving the luciferin, luciferase, oxyluciferin, 

 oxygen and reductase within the cell, with the pro- 

 duction of light and formation of more oxyluci- 

 ferin. So long as the luminous cell is resting and 

 unstimulated the tendency is for reduction proc- 

 esses to occur and luciferin to be formed. It must 

 be pointed out "that not all sorts of stimulation can 

 be explained in this way, as the stimulation of 

 muscles or nerve fibers may take place in the com- 

 plete absence of oxygen. 



The phosphorescence of Benilla: George H. 

 Parker, S.D., professor of zoology, Harvard Uni- 

 versity. The common sea-pansy, Benilla, is found 

 in most southern waters and has long been noted 

 for its phosphorescence. It is a dice-shaped colony 

 of polyps whose upper surface is covered with 

 numerous small whitish patches, the phosphorescent 

 organs. During the day Benilla can not be excited 

 to phosphoresce, but at night on stimulation it can 

 be made to glow with a beautiful golden green 

 light. The light is produced in wavelike ripples 

 that spread out from the spot stimulated and run 

 over the upper surface of the animal. They 

 travel at a relatively slow rate that agrees with 

 that at which the nervous impulses of the animal 

 travel. Hence it is concluded that the phosphores- 

 oence of Benilla is under the control of the nerve- 

 net of the animal which apparently pervades the 

 whole colony. 



Feeding habits of pseudomyrmine ants: W. M. 

 Wheeler, Ph.D., ScD., professor of economic ento- 

 mology, Bussey Institution, Harvard University, 

 and Irving W. Bailet, assistant professor of for- 

 estry, Harvard University. In 1918 the senior 

 author described and figured various stages of the 

 larvEe of Pachysima and Viticola, two genera of 

 Pseudomyrmine ants from the Congo. Except in 

 their earliest stages these larvaa have the ventral 

 portion of the first abdominal segment much 

 swollen and hollowed out as a peculiar pocket, 

 opening just behind the head. The pocket was 

 called the trophothylax (Wheeler, 1920), because 

 the food, in the form of a subspherical or lenticular, 

 usually dark-colored pellet is placed in it by the 

 worker nurses, so that it is within easy reach of 

 the larva's mouth-parts. As early as 1918 the 

 pellet was known to consist of triturated pieces of 

 insects, but subsequent careful analysis shows that 

 the pellet not only in Pachysima and Viticicola 

 but also in the two other genera of the subfamily, 

 Tetraponera and Pseudomyrma, is merely the small 

 pellet ("corpuscle enroulfi" or "corpuscle de net- 

 toyage" of Janet), which the worker ant first 

 pioulds in its own infrabuccal pocket and which 

 consists of the solid food-particles collected by the 

 Ant with the etrigils of the fore tibisB from the 

 surfaces of the antennse and other parts of the 

 body and carried into the infrabuccal pocket after 

 being wiped off by the tongue and maxillEe. Other 

 ants eventually spit out the pellet, which is com- 

 monly a moulded, subspherical conglomerate of 

 diverse particles, such as small pieces of insects, 

 fragments of plant-tissue, fungus spores and 

 hyphse, pollen grains, etc., and cast it away as 

 refuse, but the worker nurses of the Pseudomyr- 

 minsB place it as food in the trophothylax of the 

 larva. Even this, however, is not the whole story. 

 Examination of the mouth of the larva reveals a 

 singular, hitherto undescribed organ, evidently used 

 for reducing the food-pellet to such a finely divided 

 gtate that it can, when acted on by the digestive 

 juices of the stomach, yield a certain amount of 

 nutriment which the worker ant could not extract 

 from it while it was in the infrabuccal pocket. 

 This larval organ, which may be called the tro- 

 phorhinium, consists of two flat, opposable plates, 

 corresponding to the dorsal and ventral walls of 

 the buccal cavity, each furnished with very fine, 

 parallel, transverse welts or ridges, which, under a 

 high magnification, are seen to be beset with very 

 delicate chitinous projections or spinules. The 

 .ventral usually has more numerous rows of these 

 ^ructures than the dorsal surface. The two sur- 



