354 ZOOLOGY. 



treated, lived through the winter. Plant-lice werctillec'. in a hothouse 

 by similar means. Dr. Hagen therefore contends against Professor 

 Metschnikoff, that fungous inoculation can be applied to practical uses, 

 ^';d that it will not be necessary to wait till the scientific meaning of tbe 

 phenomena involved is understood ; he thinks that the plan has already 

 been successful in practice, although further experiments should be 

 made before any positive decision can be arrived at. 



THE GLOWWORMS AND THEIR PHOSPHORESCENCE. 



The structure of the LampyridiC and their phosphorescent character- 

 istics have been examined by Rev. 11. S. Gorhain.* The conclusion is 

 reached that '' the sexual instinct has played a large part in molding 

 the external structure of this group of beetles, and that it is to that we 

 must look for an adequate explanation of the development of phos- 

 l)horescent light, though not perhaps for its origin." The cases in which 

 both of the sexes have wings, and both exhibit also X)hosphorescent 

 qualities, form the larger proportion among existing species. It is con- 

 tended that in this condition the emission of light would be useful in 

 the attraction of the respective sexes and bring them together in swarms. 

 Those species, however, which are regarded as being the most typical 

 of the family and in which the parts are more specialized, are such forms 

 as Lamprocera and Cladodes. In these types the phosi)horescent faculty 

 has not been developed in the same proportion as the organs generally, 

 and the eyes, for example, are " reduced in a direct ratio with the light" 

 whenever the antenna? are enlarged in inverse ratio to the diminution of 

 the phosphorescence. Whether the eyes develop at the exj^ense of the 

 antenna', and are, so to speak, the recei)tacle of all the vital forces of 

 the head, or whether the antenna^ supijlement the loss of the other 

 organs of sense, and are useful in detecting the presence of the female, 

 only one fact is in evidence, which is that tlieplumosityof the antenna';, 

 in one case, and the enormous development of the eye, in the other, are 

 usually sexual characters predominating in the male, but sometimes 

 found in both sexes. ]\Ir. Gorham has found tbat selected sx^ecies of 

 Lampyridai may be groui)ed under three categories, viz : 



1. Species with i)lumose antenn.Te, small or moderate eyes, both sexes 

 winged, light-emifting surface confined to one or more small spots : 

 Lamprocera, Cladodes^ Testa, Lticidora, PhoenoUs, and Megalophikahnus. 



2. Si)ecies in which both sexes are winged; light emitted consider- 

 able, sometimes greater in the 9 ; eyes large, sometimes excessive; 

 antenute simple, usually filiform : Cratoynorjjhus, Lucernula, Asjyidasoma, 

 Luciola, and Photiiris. 



3. Species in which the female is apterous, or with rudimentary wings; 

 light emitted often very great in the female, and often only rudiment- 



* Gorham (H. S.)- On the structure of the LanipyridfB, Avith reference tc their jthos- 

 phoresceuce. Trans. Entomolo(jkal Soc, Londou, 1880. pp. 03-67. 



