Publ. 23. IX. 1936. 
PSYCHIDAE. General Topics. By Or. A. Seitz. 
1177 
Psychidae Case-bearers. 
As most of the peculiarities of this rare group of lepidoptera have been exhaustively treated in Vol. II 
(p. 369), Vol. X (p. 729) and Vol. XIV (p. 481) only a few remarkable traits will be dealt with here. The puzz¬ 
ling contradiction between the total immobility of the female imago and the world wide distribution of several 
of its species need only be mentioned as a number of explanations have been pointed out in the above named 
places. No other group of lepidoptera have so many chances of spreading as these where the larva when changing 
into a chrysalis adheres to every kind of object, posts, faggots, fruit, even to utensils in every day use; not in¬ 
frequently in a waterproof case not subject to any outside influences. Branches of fruit rind falling into the 
water are much more easily swept or carried away than the pupae or imagines of large Rhopalocera, as for 
instance Danais archippus, whose transportation from its (American) home to fairly remote regions such as 
Australia, New Zealand, Portugal, the Atlantic Islands, the Indian Archipelago (Jaluit etc.) has taken place 
under our very eyes so to speak. Castniidae and Central American Syntomidae have of late been repeatedly 
delivered alive to European Museums or bred from pupae which have been brought over. The invaders of the 
latter groups have not propagated, as introduction in sufficient numbers for copulation is hardly possible by 
this means. In the case of the Psychidae parthenogenesis takes place to a greater degree, as was pointed out 
in discussing the group in the volumes mentioned of the “Macrolepidoptera”, so that the occasional drifting 
in of a single branch with a $ pupa clinging to it may lead to complete naturalization. The fact that such 
parthenogenesis has not yet been satisfactorily proved among the extremely similar forms of the Oiceticinae 
which are spread all over the southern hemisphere, does by no means exclude such a possibility, as just the 
Psychidae have revealed the amazing phenomenon that the same species is able to propagate in some districts 
entirely parthenogenetically, in others, however, constantly and in others again frequently sexually. It would 
therefore not be very surprising should this parthenogenesis come about in cases of artificial transportation 
also among species where, under normal conditions, it has never been observed, as it has been similarly observed 
among numerous insects of other orders as an adaptation to seasonal changes. 
In addition to these qualities so favourable for conquering new patriae there are numerous others directed 
to the same effect. Just with certain Oiceticinae the eggs, even in regions without any real winter, often lie for 
weeks and months without releasing the little larvae, and it is not impossible that, as it frequently happens 
in the animal world, they await better conditions before emerging from their case. Moreover, we find an aston¬ 
ishing polyphagia among many Oiceticinae. Breedings of Oik. geyeri and kirbyi platensis, which I carried out 
in the Frankfort Insect House proved the suitability of nearly all the foliage trees of the Zoological Gardens 
there as welcome food for the larvae, especially willows, plane-trees, Robiniae and many kinds of timber; only 
certain poisonous plants such as nerium and eucalyptus were disdained, and conifer needles were only slightly 
gnawed and then abandoned. 
The temporary frugality of certain otherwise very greedy widely distributed Psychidae is also wonderful. 
While one is accustomed to find little power of resistance to hunger just among polyphagous sorts, the Arctiidae for 
instance, the Oiketicus can do without any food for a very long time without showing any noticeable change 
in condition. Even the lack of fresh green food for a long time is not necessarily injurious, for if it once happens 
that all vegetable food fails, the larva which often accepts the driest leaves without distinction, stalks and all, 
even seeming to prefer them to fresh food at times, has another means of fighting starvation. \\ hen food is 
plentiful it cuts differently sized bits out of the leaves and fastens them outside on its case as if for decoration. 
Then, when food gets scarce, it rips these bits out of its case and devours them, no matter how dry they may 
be, patching up the holes produced in the bag with silk web. 
VI 
148 
