142 Dr. T. A. Chapman on Heterogyna penella. 
The most specialised peculiarity of this moth (ZH. 
penella §) is that it emerges from its cocoon and pupa 
case, remains outside until the male is attracted and for 
a bare ten minutes after, and then re-enters its pupa 
case. This drops back into the cocoon, and the appear- 
ance is the same as if the moth had never emerged. The 
mechanism by which this manceuvre is accomplished by a 
maggot without appendages is very interesting. 
Until last year (1897) I had never met with the species 
in sufficient numbers to make any observations of value ; 
I had found the female pupa case a very puzzling 
structure, and not having seen the male pupa, could form 
no idea of its relationships. Last spring, however, I met 
with it freely at Digne and have been able to observe it 
very fully. 
Whilst Heterogyna penella inhabits a large part of 
Southern Europe, it would appear that the Basses Alpes 
are its headquarters, and in some districts of this depart- 
ment it has even been described as destructive; it is not, 
therefore, surprising that Digne affords it in plenty, at an 
elevation of 2,000 to 3,000 feet. I do not think it is at 
all common towards the Mediterranean coast, but it 
descends to lower levels and a warmer climate than 
Digne, whilst I have also taken it at Lauteret at 8,000 
feet, where intense cold obtains in winter, and the sum- 
mer is comparatively short. Sucha range of climate, with 
so narrow a geographical range is difficult to understand. 
As I am not aware that it is anywhere double brooded, I 
conclude that, in its warmer habitats, it goes into hiber- 
nation before midsummer. 
The larva is full-fed at Digne about April 20th to 30th, 
at Lauteret nearer the end of June. The males are 
full-fed quite ten days before the females. 
To spin their cocoons the males seek a dead twig of the 
food plant (chiefly broom at Digne) or a dry stem of grass, 
against one side of which, usually in a prominent and 
conspicuous position, they spin a spindle-shaped cocoon 
of silk, at first white, then turning golden-yellow, of a 
somewhat open texture, so that the contained larva or 
pupa is easily seen. A large proportion of these at once 
produce parasitic dipterous larva; only twice were any 
other parasites produced, these were chalcids. 
The diptera emerge in confinement in six or eight 
weeks, certainly too early to infest the next brood of 
