1864. | Zoology and Physiology. 515 
which these hermaphrodites issue, are laid in the workers’ cells, and 
ought, therefore, to become workers, but the queen-bee, having pro- 
bably some defect in organization, a part of these eggs are only incom- 
pletely fecundated, so that the development of the female organs 
remains in a more or less rudimentary condition. 
The cultivation of silkworms is so important a branch of industry 
in some portions of the globe, that any information respecting their 
diseases and modes of cure becomes highly valuable. Captain Hutton, 
F.G.S., of Mussooree, N.W. India, attributed the enormous loss of 
worms by “ muscardine”’ and other diseases to the combined effects of 
bad and scanty food, want of sufficient light and ventilation, too high 
a temperature, and the constant interbreeding for centuries of a debili- 
tated stock. He regards, after long experience, the occasional occur- 
rence ina brood of one or more dark grey or blackish brindled worms, 
—the vers tigrés, or vers zébrés—as an attempted return, on the part 
of nature, to the original colours and characteristics of the species ; in 
fact, the dark worms, hitherto rejected by the sericulturist, were the 
original and natural worms, and the whiteness or pale sickly hue of 
the majority was a positive indication of degeneracy and the destruc- 
tion of the original constitution. He recommends the sericulturist to 
separate his dark worms from the general stock, and to set them apart 
for breeding purposes, thus annually weeding out all the pale-coloured 
worms. 
M. Onesti has found that wood-soot, if sprinkled over silkworms 
attacked with /ébrine, effects an almost certain cure, or, at all events, 
prolongs their lives until the cocoons are finished. The French 
Minister of Agriculture has addressed a circular to the préfets of the 
sericultural departments of France, and has requested that a com- 
mission be formed to report on the value of M. Onesti’s discovery. 
Professor N. Wagner has discovered a fact in natural history, 
which at first sight appears incredible; but it is supported by prepa- 
rations, an inspection of which has convinced Professor de Filippi of 
the truth of the observations. Professor Wagner found in June 1861, 
under the bark of a dead elm, some whitish apodal worms, which 
proved to be the larvee of insects. Each larva was filled with smaller 
larvee, at first supposed to be parasitic; but the smaller larve were 
found upon closer examination to be identical, even to the smallest 
details, with the enveloping larvee, by which identity Professor Wagner 
was led to assume that the included larve represented a second gene- 
ration produced by the enveloping larva. This would be a case of 
alternation of generations, even more surprising than that of the 
aphides; and this interpretation has several circumstances in its 
favour, viz. the identical character of the inclosed and enclosing 
larve—their simultaneous development—the presence of enclosed 
larve not in some but in all the larve—and, lastly, that in the inte- 
rior of the larve of the second generation, a third generation is pro- 
duced precisely similar to the first two. Professor Wagner has 
observed three other species of the same genus, all presenting this sin- 
gular mode of reproduction. The perfect insects are still unknown, but 
from the appearance of the larvee, they seem to be of the order diptera. 
