1922] 
Possible Pedogenesis in the Blow-fly 
129 
December, 1919, 502 eggs were hatched in this waj^ and in no 
instance did an egg produce more than a single larva. It was 
therefore concluded that Calliphora gave no evidence of poly- 
embryony such as has been found so abundantly in certain 
hymenopters. 
To test again the possible production of maggots from other 
maggots, the experimental procedure of April 2, 1919, was 
repeated. On October 2, fifty jars were set up with fish-meat. 
They were examined on October 28 and were found to contain 
no maggots. On the next day into each of twenty-five of these 
jars a single newly hatched maggot was introduced and the 
remaining twenty-five were kept as checks. On November 10 
an examination of the jars showed no maggots in the twenty-five 
check jars, no maggots in three of the infected jars, probably 
because of accidental death, one maggot each in twenty of the 
infected jars, eight in one infected jar, and twenty-one in another. 
The maggots in the last two jars were carried on to pupation 
and hatched. All proved to be Calliphora erythrocephala. Of 
the eight in the first jar, five were males and three were females. 
Of the twenty-one in the second jar, five failed to hatch, nine 
emerged as males and seven as females. 
On October 18, a second set of fifty jars was started in the 
same way as in the preceding test. On November 15 these jars 
were examined and found to contain no maggots showing that 
they had not been accidentally infected. Into each of twenty- 
five of them a single newly hatched maggot was introduced and 
the jar closed. On November 26 pupation was completed and 
an examination of the set showed that the twenty-five check 
jars were without pupae as well as six of the infected jars; eighteen 
of the infected jars contained each a pupa, and one contained 
seven. These seven were subsequently hatched and all proved 
to be Calliphora erythrocephala, four females and three males. 
The tests of October 2 and October 18 were carried out 
with such precautions that it seems impossible that the results 
could be due to accident. The increases observed have always 
occured in the autumn and never in the spring and 1 am, there- 
fore. led to believe that in October and November or even later 
/ 
