Ву. es 
The sting of Ceratina is almost completely atrophied and never т 
use; instead of it, to defend themselves and their nests, the Ceratinae 
secrete a yellow saliva, vigourously scenting of lemon zest. 
If a Ceratina is seized across the body with a forceps, it hastily 
Strives to displace its fragrant secrete upon the instrument, by means of 
its fore and then middle legs. When the Ceratinae are expulsing earwigs 
from their nests, this odour of 1етоп zest is sometimes perceptible. The 
usual presence of the mother-Ceratina in the upper part of the ‘nest 
makes the building up of a stopple quite useless. 
After completing the building of cells in one nest, Ceratina under- 
takes sometimes the construction of a new, secondary one, which is gene- 
rally similar to the first, primary, but not as regular and complete as the 
latter. So, in the secondary nest there are but 1—2, less frequently 3—4 
cells, usually separated by a complicated system of transversal septae which 
are very carelessiy made. Such nests are built in the second half of July 
and beginning of August and occur but rarely in comparison with the pri- 
mary ones. In the end of August the young Ceratinae leave their pa- 
ternal roof, while their mother dies in the deserted nest, half of September 
at the latest. 
The assertion of some authors (Verhoeff 1892, Comstock 1895) 
that the Ceratinae possess a double generation is very doubtful; direct 
observations show that Ceratina callosa has but one generation in the year. 
In conclusion, the author discusses the main characters in the life of 
the Ceratina from a phylogenetical point of view. Here the author calls 
the attention of the reader on the main biological characters common 
to the Ceratinae and Halicti (as, for instance, the fact of encounter of the 
mother-bee with her young just developed), and seeks to explain the dif- 
ferences in some details of the life of both. 
The Ceratinae and Xylocopae have a common ancestor; this hypo- 
thetical insect was nestling in a dry and hard soil. The nest, as usual in 
the earth-living bees, was of branched type. The Ху/осорае are nearer 
related to this ancestor than the Ceratinae; so, colonies of Xylocopa oli- 
vieri, occurring in Turkestan, after the author's own observations, are nest- 
ling in similar conditions (earthen walls). 
The following chief moment in the phyletic history of the Ceratina 
and Xylocopa was, when the ancestors of the Ceratinae and typical Xylo- 
copae abandoned their underground nests in order to build them in halt 
decayed wood. 
As in these new conditions, where there were still no special means 
of resistance against humidity (as cocoons, water-impermeable lining of the 
cells), it was very hard to live throughout the long periods of rains and 
cold, a new important phenomenon took place at that time in the life-cyclus 
of the Ceratinae and Xylocopae; this phenomenon, occurring every au- 
tumn, consists in the escaping of the young bees from their nest to seek 
new, dry shelter for the winter. 
