ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
419 
follows a special account of the more continuous analogous processes 
in the history of the antenniform organ of the larval Thrixion. 
Facetted Eyes of Arthropods.*— Mr. V. L. Kellogg calls attention 
to Zimmer’s recent description of the differentiation of the facetted eyes 
in the males of Chloe and certain other Epliemerids. This is to he 
compared with the two kinds of eyes which Chun has described in 
Stylocheiron and certain other genera of pelagic Crustacea. The author 
has found two kinds of facetted eyes in Blepharocera capitata , a North 
American nematocerous Dipteron. The predaceous individuals (both 
male and female) have facetted eyes of two kinds, while the other form of 
female which feeds on nectar has only the usual small-facetted strongly 
pigmented eyes. It seems likely that the differentiation implies a certain 
adaptability of the vision to various conditions of focus and intensity of 
light. 
a. Insecta. 
Hybridising Species of Tephrosia.f — Mr. J. W. Tutt gives an 
account of recent experiments made by Dr. Riding and Mr. Bacot in 
hybridising the two allied species Tephrosia bistortata Goeze ( crepus - 
cularia auct.) and T. crepuscularia Hb. (biundularia auct.). Some of 
the more important conclusions to which the experiments point are the 
following : — (1) The intercrossing may result in every possible inter- 
mediate stage of fertility from sterility to full fertility. (2) Certain 
crossings produced almost entirely male offspring. (3) The hybrids 
are fertile inter se , but to a less extent than in the parent stock, i.e. there 
appears to be a larger proportion of failures. They are also fertile with 
the parent stock. (4) The direct hereditary influence exerted by the 
parents is a great one. (5) The phylogenetically older species is more 
dominant in stamping its characters on the progeny. (6) The sex- 
condition of the hybrids depends on the predominating influence exerted 
by one of the parents. (7) A recently formed aberration may be pre- 
potent and dominant over the type from which it has but recently 
sprung. (8) The re-crossing of a hybrid with one of the parent species 
produces offspring scarcely differing from the parent species with which 
the hybrid has been paired. (9) The inbreeding of the same cross 
produces a large percentage differing much from either parent form. 
(10) The crossing of the hybrids obtained from original reciprocal 
crosses tends to produce a mixed progeny, some referable to known 
forms of the crossed species, others quite unlike anything ever obtained 
in nature. (11) The darkest, best-marked, largest, and most vigorous 
specimens are those which remain longest in the pupal state. (12) The 
hybrids have lost all regularity as to the time of emergence, i.e. hybridity 
causes continuous-broodedness. 
As to sex, Mr. Tutt also notes that the influence of the male parent 
is less than that of the female. When T. bistortata is the male parent 
the progeny is more vigorous than when T. crepuscularia is the male 
pare nt. The greater vigour of the male results largely in the produc- 
tion of female offspring. When the male is of the dominant species, 
females are developed in fair proportion ; when the female is of the 
* Zool. Anzeig., xxi. (1898) pp. 280-1. 
f Trans. Entom. Soc. London, 1898, pp. 17-42. 
