of the Oil Beetle, Melo. 305 
season. Goedart found the eggs of M. prescarabeus, deposited on the 12th 
of May, produce larvee on the 23rd of June, a period of forty-three days ; 
while DeGeer shows that eggs deposited by this species on the 18th of May 
produced young on the 19th of June, a period of only thirty-three days. In 
the packets of eggs watched by myself, I have found a much greater dif- 
ference in the time of evolution. The first packet of eggs, obtained on the 
8th of April 1830, and inclosed in a tin box on the window-sill of my cham- 
ber, were developed early on the morning of the 25th of May, a period of 
forty-seven days; while another packet, deposited by the same species, 
M. violaceus, on the 26th of April 1842, produced young on the 2nd of June, 
a period of thirty-three days. From other eggs deposited by M. proscarabeus 
on the 29th of April, the larvae came forth on the 3rd of June, a period of 
only thirty-six days. In another instance, from a packet of eggs deposited on 
the evening of the 1st of May, some of the larvee came forth on the 3rd of June, 
or at thirty-four days; while the greater number of them did not come forth 
until the 5th, and a few remained until the 6th. Those of another brood, 
deposited on the 30th of April, and placed under precisely the same circum- 
stances in regard to locality and temperature as the last, also made their 
appearance on the 6th of June. On the other hand, larve were produced on 
the 14th of June from a packet of eggs that were deposited on the 24th of 
May, an interval of only twenty-one days. During this latter period the 
temperature of the atmosphere was very much higher than in the earlier part 
of May and April, and ranged from 70° Fahr. upwards. On the 13th of June, 
the day before the larvee came forth, it was as high as 81° Fahr. 
From these facts we may conclude that the average period of the egg is 
from four to five weeks; but that the evolution of the embryo is accelerated 
or retarded by the higher or lower temperature of the season. 
When the embryo is fully developed, the egg-shell is burst at its largest 
extremity, and a little hexapod larva, an active, diminutive creature, that has 
long been the subject of discussion, gradually withdrawing from its foetal 
envelopes, presents itself to view as the progeny of Meloé. 
So exceedingly dissimilar in every respect is this microscopic and agile 
little being to its héavy-bodied, slow-moving parent, that we can hardly be 
surprised that those who have not actually witnessed its evolution from the 
