622 
SUMMARY OP CURRENT RESEARCHES RELATING TO 
absence of food, &c., can be survived. The various effects of diminished 
nutrition on the individual, on pupation, on the number of offspring, are 
spoken of. It is recognized that fasting may be associated with pro- 
gress. The choice of food-plants and its motives, the causes of change 
of diet, cannibalism, the influence of nutrition on reproduction, the rate 
of growth and its limit, moulting, and water-drinking are among the 
subjects discussed in this essay, which is full of interest to the student 
of biology and bionomics. 
Evolution of Papilionidae.* — Prof. G. H. Th. Eimer answers a 
criticism brought against him by Herr A. Spuler. f By his study of 
Lepidoptera Eimer endeavoured to show how species arise “ by definite 
modifications in a few directions,” one species differing from its nearest 
neighbours in the relative predominance of certain characters — in short, 
that species form definite morphological series. The specific distinctions 
are not only not indefinite, they are not explicable on a utilitarian 
theory. Eimer supported this view in a large work and atlas ; Spuler 
disputed the accuracy of certain facts and the legitimacy of the conclu- 
sions ; Eimer answers that Spuler fails to make good his criticism, and 
that he has not read the book with sufficient care. 
Respiratory Phenomena in Chrysalids of Silk Moth.f — Prof. L. 
Luciani and Dr. D. Lo Monaco have made daily and nightly quantitative 
estimates of the amount of C0 2 given off during twenty-two days. The 
oscillations demonstrate that the life of the chrysalis may be divided 
into four periods: — (1) Along lethargy of four days, (2) a long activity 
of seven days, (3) a short lethargy of two days, and (4) a short activity 
before emergence. The authors, of course, regard the fluctuations in the 
amount of C0 2 liberated as indices and, to some extent, measures of the 
intensity of the vital processes occurring within the chrysalid. 
Remarkable Behaviour of the Spermatozoa of Dytiscus margi- 
nalise — Prof. L. Auerbach has observed the spermatozoa in their 
passage through the convoluted seminal vesicles. All those arising from 
one testicular follicle are united in a bundle. Each has a very complex 
structure, bilateral but unsymmetrical. The right side of the head is 
concave, the left convex ; the whole head is longitudinally curved to the 
right or left ; and on the posterior half of the right side there is a pro- 
jecting ridge bearing a hook-shaped “ anchor.” Of the entire structure 
a careful description is given. At the free end of the cyanophilous 
anchor an erythrophilous spherule appears. But the most remarkable 
fact is that the spermatozoa unite in pairs in a perfectly definite fashion, 
opposed and crossed in a manner somewhat suggestive of a pair of 
scissors, with the right sides of the heads in contact. During this 
conjugation, or “ dejugation ” as Auerbach calls it, the anchors change 
in form, and the little spherules are lost. Hundreds of these double 
spermatozoa are found together in little balls. The conjugation is a 
temporary one, but it may permit a molecular exchange of substance, 
perhaps with the result of mixing the hereditary qualities and limiting 
variability. 
* Zool. Jahrb. (Abth. Syst., &c.), vii. (1893) pp. 186-205 (8 figs.). 
f See this Journal, 1892, p. 469 ; 1893, p. 174. 
t Bull. Soc. Entomol. Ital., xxv. (1893) pp. 12-24. 
§ SB. K. Preuss. Akad., 1893, pp. 185-203 (2 figs.). 
