218 
Here too, the after-effect in the 1“. harvest is again clearly 
observed. Properly speaking, it might be expected that this after- 
effect should be continued in a few harvests more, as the slice- 
larvae, after the 2°¢ harvest series, looked so much bigger and more 
vigorous than those of the dry jar. As a matter of fact the longer 
duration of the after-effect under discussion (in this as well as in 
the previous trial series) clearly finds expression in the circumstance 
that the differences of the deathrates between the two trial jars ever 
increase up to the 4" harvest. So, if as a final result it is stated 
that the mortality figure in the slice-jar has fallen by 18.5 °/,, this 
figure is certainly not flattered, but estimated too low, a good deal 
too low if one considers carefully the figures and the circumstances 
under which they were obtained. 
The supposition mentioned on page 211 that the gnawing of the 
pupae might be a consequence of the larvae’s need of humidity is 
corroborated by comparing the numbers of dead pupae mutilated or 
not, harvested from the two jars. 
From thetable on the former page it is seen that in the jar without slices 
77°/, of the dead pupae were eaten at, and by far most of them 
very strongly, whereas in the slice-jar this figure was only 15 °/, 
and even then so slightly that often doubt arose as to whether or 
not they had to be noted down as “eaten at”. 
The determination of the average mortality among the eggs, larvae, 
and pupae was to me of this practical signification that once I knew 
this, the approximate quantity of eggs for a given culture could be 
fixed, in order to get at my disposal a desired number of beetles. 
The outlay of too large a number of eggs was a needless labour 
and waste of time, leaving apart the drawbacks connected with it. 
The labour spent on the fixing of these figures in the first three 
years of experiment, has been amply rewarded by the use made of 
them. The average deathrate of eggs + larvae + pupae to each 100 
eggs laid out amounts to the considerable figure of about 58 °/,. 
LITERATURE. 
1. Breum. Tierleben. Insekten. 
2. FRENZEL. Ueber Bau und Thitigkeit des Verdauungskanals der Larve des 
Tenebrio molitor Berl. Entom. Zeitsch. Bd. XXVI. 1882. 
3. Frisco, J. L. Beschreibung von allerlei Ins. in Deutschland 1720. 
4. SALING, TH. Zur Kenntnis der Entwickelung der Keimdrüsen von Tenebrio 
molitor. Inaugural Dissert. Marburg 1906. 
5. Sturm, JAKOB. Deutschlands Fauna in Abbildungen uud Beschreibungen. 
V. Insekten. Kafer. 
Utrecht, February 1920. 
