Puhl. I. VI. i9ii. OECETICINAE. By Dr. E. Strand. 



353 



cases back; some bore the experiment well, but the majority died if leftexposedforsomelengthof time, and it was 

 evident that the large and almost full-fed Oiketicus were hardly or not at all able to spin quickly another case. 



The moths, as is self-evident from their atrophied mouth-parts, do not feed at all and have therefore a 

 very short life. The ^^ soon die after copulation. The $$, which hardly lead the life of a Lepidopteron in 

 the ordinary sense, commence to oviposite soon after copulation. It appears that fertilisation is effected by 

 the sperm soaking into the lump of eggs of which the greater part of the ?-body consists rather than by impreg- 

 nating each egg singly. In some cases parthenogenesis has undoubtedly been established, the occurrence of 

 which is evident from the fact that the 3'^ do not occur evervwhere or not in every brood. But it has also 

 been suggested — though by no means proved ~ that parthenogenesis occasionally occurs also in other species 

 which normally are bisexual. The single experiment I made in this respect had negative results. In Buenos 

 Aires I collected 6 female cases each producing hundreds of larvae. About 100 $-cocoons obtained from them 

 I separated from thccJ-cocoons, but although they certainly contained 20 — 30000 eggs I did not get a single 

 larva. This appears to prove that parthenogenesis does not occur in some species or only as an exception. 



About 200 Psychids are now known, of which Kirby enumerated in his Catalogue 193. The figure 

 does not give us a correct idea of the number actually existing. One does not frequently meet with these often 

 inconspicuous moths, as their time of appearance and the localities where they occur are often very restricted 

 and rearing of the larvae is difficult on account of the often slow growth. The great incompleteness of our 

 knowledge of the Psychidae is best proved by the fact that more species are known from Ceylon, where Psychi- 

 dae have been specially collected, than from the whole rest of British India. About 100 forms are known from 

 Europe, which is well-explored, and not even a dozen are described from the large Ethiopean Region. It fol- 

 lows that many Psychidae are known everywhere they have been well-collected and bred, and only in places 

 where this has been the case. 



If a general survey of the distribution oi Psychidae shows us that these in.sects are exceptionally widely 

 distributed, occurring all over the globe from New Zealand to Ireland and from Cape Horn to Kamtschatka, 

 and are even represented on remote groups of islands, such as the Canaries, it is difficult at first sight to under- 

 stand how that is possible, considering the $9 are not only wing-less but also abutely without the faculty 

 of locomotion. How^^ver, the enigma explains itself if we consider the following facts. 



First of all, the Psychidae are not monophyletic, i. e. are not branches of one and the same stem, 

 so that the forms existing to-day m Tasmania may very well be derived from quite a different branch of Lepi- 

 doptera than, e. g., the species inhabiting Sweden. Further the larva possesses quite exceptional means of 

 dispersal. Being protected by its case it wanders about and penetrates into every nook and corner where ve- 

 getation is to be found. The case is waterproof, so that the insects can even exist where the waves of the 

 sea reach them. At the rocks in Botany-Bay in Australia I found directly above the surging surface of the 

 sea finger-long cases of Psychids which were splashed with foam and water by each wave, and when I open- 

 ed them I found live and evidently healthy larvae. With this power of endurance it must be possible for 

 the larvae which come into the water with floating wood also to cross the seas and thus to reach by and by 

 new islands and continents. It is very likely that, as in our genus Apterona, there are also exotic forms 

 which become parthenogenetic perhaps under certain difficulties of existence, and in such instances the intro- 

 duction of a smgle $-case with the enormous number of eggs contained in the body of the $ would be suffi- 

 cient to establish the species successfully in a new country. Even a larva would be sufficient, as a branch 

 of a tree floating in the ocean would provide sufficient food in its bark and covering of lichens for many species 

 of Psychids — which are usually very pol_y[)hagous and also subsist on dead vegetable matter — • on a voyage 

 of weeks' or months' duration. During one of the frightful gales in which I was caught on the Pampas of 

 Uruguay in a place without any woods branches of trees fell to the ground which the wind had carried for 

 miles over the plains. On examining the branches in order to find out from the species of tree the place of 

 its origin, I discovered Psychid cases containmg young larvae. These little caterpillars were unharmed and at 

 once attacked the food. Moreover, no larvae known to me endure actual hunger so well as those of the Psy- 

 chids, be it that they can really exist for weeks without food and moisture, be it that the dry bits covering the 

 case prevent them from dying. Once I had collected on a desert herb in North Africa larvae of Amicta 

 quadrangukiris and had them so packed away in my luggage that I could only reach them and take care of 

 them after many days of absolute starvation. But they were none the worse for it and I reared them without 

 difficulty on the peal of apricots. As this power of resistance to adver.se circumstances is coupled moreover 

 with a certain indifference to temperature, the distribution over the whole globe is understandable. 



a. Subfamily: Oeceticinae. 



In the forewing veins 1 c and 1 b anastomose, the latter sending more than one branch to the hind 

 margin, 1 a and 1 b .separate at the base, then coincident. The cell of both wings divided by a longitudinal 

 vein forked at the end. Fore tibia usually with a long thorn. 



II 45 



