4. BULLETIN 766, U. S. DEPARTMENT OF AGRICULTURE. 
In the description of the larva Bouché neglected to speak of a 
very important point, the anal hooks of the first-stage larvae. This 
character has been found only in one other tachinid first-stage larva, 
that of the closely allied genus Dexodes. It is very easy to deter- 
mine this stage by these hooks and to verify the fact that Comp- 
silura parasitizes early-stage brown-tail moth larve in the fall, as 
has been found from various dissections. Pantel describes and illu- 
trates these hooks in “La Cellule.” (Fig. 1.) There are three of 
these peristigmatic hooks; two prestigmatic and one retrostigmatie. 
It is with these hooks that ‘he 
larva attaches itself to the peri- 
trophic membrane just previous 
to molting into the second stage. 
As the larva grows, the molt skins 
are pushed down on to this fun- 
nel until just previous to emerg- 
ing, when the full-grown third- 
stage maggot breaks loose and 
forces itself out of the dead host. 
This is done in the following 
manner: The anterior end of the 
parasite, assisted by the mouth 
Fig. 1.—Compsilura concinnata: Posterior hooks, makes a small Mckee a. 
stigmata and peristigmatic hooks of the integument of the host and by 
first-stage larva. a, Prestigmatic hooks, a gradual process of extending 
paired; b, stigmatic plate; c, retrostig- 5 3 
matic hook; d, sensory terminations, and retracting the anterior part 
cae eae Tat atcha of the body the larva finally suc- 
folds over the stigmata as two grasping ceeds in passing out. If the host 
Bue megniied.  (Redrawn from is one that has spun a cocoonsihe 
parasite larva will pupate within 
this, but if not, it will drop to the ground or pupate near the host. 
The time between emergence of the larva and pupation is governed 
by such things as temperature and location, whether on a tree trunk, 
in soil, or elsewhere. 
DISTRIBUTION IN EUROPE. 
Compsilura concinnata is found in Europe in practically all of 
the territory covered by the brown-tail moth. It has been imported 
into the United States from 10 European countries and possibly from 
Japan. Very little work has been done with the parasite in Europe 
beyond Pantel’s investigations. Compsilura has been described 
under a number of synonyms by various authors, and reference to 
these synonyms can be found in the “Katalog der Paliarktischen 
Dipteren,” Volume III. 
1 See also “ Bibliography,” pp. 25-26. 
