294 
ME. A. D. MICHAEL ON THE LI FE-HISTOKIES 
move about very slowly; but the day after it bad collapsed and 
was dead. There was now only one Ilypopus left ; this did not 
move nor show any sign of life ; but, on the other hand, it did 
not collapse, and in this condition it remained for nearly four 
months. I watched it every day without seeing any change 
until the 24th May, 1886, on which day a healthy nymph of G. 
spinipes emerged from the Hypopial skin. 
While this experiment was progressing I had also watched the 
cell in which I had placed the cases : one nymph of G. spinipes 
had appeared in the cell and one case was open at the posterior 
end ; otherwise there was not any change. But on the 26th May 
I found two more cases open and two Hypopi had apparently 
crawled out of them ; on touching these Hypopi they appeared 
inert and incapable of motion, but a few days after nymphs of 
G. spinipes e merged from them. 
In October 1S87 I again obtained more material from the 
same chaff-house, and also from another farm some fifty miles 
distant from the first ; this latter contained G. domesticus. In both 
samples the Glyciphagi were numerous and the larvae and nymphs 
were abundant, but I could not find any cases or any trace of 
Hypopi in either. 
In January 1S88 I once more took up the investigation : I 
obtained material and sweepings from the same chaff-house and 
again found the reticulated cases of G. spinipes-, most of them 
were open at the posterior end, the occupants having emerged. 
I put seven of the full cases in a separate cell ; in one of these 
cases I could easily distinguish a Hypopus moving its legs. I 
also found one which had apparently come out of the case, and 
which was capable of the same amount of motion ; it was from 
this specimen that fig. 9 was drawn. On February 6 I found 
that one of the seven cases was opeu and that a nymph had 
emerged from it. I isolated this in another cell, which I will 
call cell 5. On February 8 another nymph emerged from a second 
of the seven cases. I placed this nymph also in cell 5. On 
February 9 an adult G. spinipes emerged from one of the nymphs 
in cell 5, the second nymph also was inert. Ou February 26 an 
adult of the same species emerged from the remaining inert nymph. 
From this time up to the end of April, when I closed the 
observations, nymphs of G. spinipes continued to emerge at inter- 
vals from the remainder of the seven cases, and from other cases 
which I had put in different cells, and adults continued to emerge 
