58 — 
То the food, stored up for Из larva, the insect gives а particular 
form, that of a cake (fig. 2, р. 16; р!. Ш, fig. 3 and 4). It fastens the latter 
by a small part of one of its broad sides to the lateral wall of the 
cell, at a considerable distance from its bottom. The so obtained iso- 
lation of the ,cake“ from the cell-walls preserves it sufficiently from 
dissication. 
The absence of either special lining in the cells of Ceratina callosa 
is fully compensated by this original manner of storing up the food. 
As to the consistence of the provision, it is, when fresh, that of a half- 
liquid paste, but during long periods of rain it turns liquid and assumes 
the shape of a drop which spreads in the course of time all over the 
cell. In such cases the larvae usually perish of mould. Simple experiments 
confirm these conclusions. 
The egg of Ceratina callosa is attached by its posterior end to the 
cell-wall, under the food-store, its anterior part touching the under surface 
of the latter. From a series of circumstances there results the neces- 
sary conclusion, that in this case Ceratinae behave like the other so- 
Шагу bees (with some limitations also like the social bees), that is, that 
they store up the provision before laying the egg, the difference being but 
in placing the egg underneath the food-cake. 
The scantiness (almost full absence) of hair-covering on the skin of 
Ceratinae, as well as the dorsoventral compression of their body, enable 
them to force their way easily through the narrow passage between the 
food-cake and the cell-wall opposite to the attachment point of the pro- 
vision in order to lay the egg on the spot mentioned above. 
In this extraordinary way of egg-laying the „sanitary“ instinct of the 
Ceralinae is manifested. After hatching and consuming a half of the food 
their larva begins to escrete dejections; the latter fall to the bottom of the 
cell without being mixed with the food (a mechanical mode of separa- 
ting nutriment from excreta; pl. Ш, fig. 5). 
The bees of the genus Osmia, living in conditions similar to those of 
the Ceratina (for instance О. leucomelaena K by), lay their eggs upon the 
food placed on the cell bottom; but in this case the larvae attach their 
excrements themselves to the ceiling of the cell (an instinctive mode of 
separation). Yet it is well known that in other cases the rectum of the 
larva is usually separated from the rest of the intestine and a communi- 
cation between these parts*is established but after nutrition is completed 
(a physiological mode). The artificial mixing of the food and excreta is 
usually accompanied by the death of the larva. 
Every cell in the nest of Ceratina callosa has, as a rule, its parti- 
cular bottom and roof, so that a cavity between the roof of the preceding 
and the bottom of the following cell is secured (pl. Ш, fig. 6, 8). Similar 
mode of construction the author observed on the wasps of the genus Ody- 
nerus, and described it as „double partitions“ (to discern them from „ordi- 
nary“ ones). After the authors calculations about 82 per cent of the 
total number of septae in the nests of Ceratina callosa are double ones. 
