TACHINID PARASITES OF THE GIPSY MOTH. 211 
earth for a distance of several inches in quest of puparia which have 
been buried therein, and since they can pass through well-nigh invis- 
ible cracks and are in possession of an acute maternal instinct, they 
are able to enter receptacles of all sorts by means of openings far too 
small to permit the passage of any other among the secondary para- 
sites which have been studied, not excepting those from the gipsy- 
moth eggs. 
Having located their prey, oviposition follows, the eggs are de- 
posited upon the surface of the nymphs in an irregular circle sur- 
rounding a wound made by the ovipositor. They are very small but 
appear to swell somewhat before hatching, and if the puparium is 
broken open so that they are freely exposed to the air, they will not 
hatch at all. Contrary to expectations the larve and their mode of 
life presented nothing abnormal. The number of larve or pupe 
which had been found in the hibernated Blepharipa in the spring of 
1907 was so extraordinarily large in comparison to the size of the 
mother insect that it was considered likely that some form of polyem- 
bryony or pedogenesis would be found upon further study. 
Becoming full fed, they will pupate immediately if the temperature 
is uniformly high, but will hibernate if it is allowed to fall below a 
point which was not determined. As soon as pupation has taken 
place the sexes are easily separable, through the absence of wings and 
eyes in the males. The male pupz develop much more rapidly than 
the females and the adults issue in advance of their mates. They are 
invariably in the great minority, and their relative numerical strength 
is still further reduced through the terrific duels which follow their 
emergence. Notwithstanding their physical defects in the matter of 
sight and powers of flight, their seeming weakness otherwise, and 
their small size, even when compared to their mates, they possess a 
courage and a vigor that is most surprising. In the instance of a 
colony which had been removed, from the puparium in which it was 
reared through its early stages, to a small glass cell, the several males 
which issued well in advance of the females engaged forthwith in con- 
flict, in the course of which a considerable number was killed. The 
survivors of this Lilliputian battle royal calmly awaited the issu- 
ance of the members of their harems and proceeded to mate with one 
and all with an ardor which seemed to know no limit. 
Mr. Smith also conducted an experiment in parthenogenesis, the 
results of which were and remain unique in the annals of the labora- 
tory. As in every other instance in which an attempt has been made 
to secure parthenogenetic reproduction with the hymenopterous para- 
sites, it was successful, but in this case to a limited degree only, in 
that the females positively refused to deposit more eggs than they 
would normally have produced males had they been properly fertilized. 
Instead of depositing sufficient to provide for the complete consump- 
