352 PSYCHID^. — Introduction. By Dr. A. Seitz. 



removed Oiketicus-\a,rvae from their case, and inducing them to crawl into that of another caterpillar they at 

 once set to work to make it comfortable. When after 2 or 3 daj'.s I placed their o^^^l case before them, they 

 rejected it and remained in the new one. 



The cases of the full-fed specimens are very diverse in shape. Some are simple tubes of sand, sometimes 

 wound spirally like a shell. The Australian Entometa ignobilis Walk, places parallel on the outside of its case 

 small bits of twigs, some of which stick out at the ends; and Herr Heylaert.s. of Breda, was so kind as to 

 send me cases of the African Eumeta moddermanni Heyl. which are similarly constructed. On the other hand, 

 the Australian Thyridopteryx huebneri Westw. makes cases which are covered with bits of leaves placed in 

 tile-shape one over the other, so that the silky house is entirely concealed. Oiketicus geyeri from Buenos Aires 

 and Montevideo fastens small t^vigs to its silky case, which are transverse, oblique and raised so that an ill- 

 defuied mass is formed. Metura elongata, from South Australia, on the contrary constructs regular long tubes 

 resembling a cigar in size and shape, on wliich bits of twigs inches long are placed parallel at rather regular 

 intervals. Herr Jose Steixbach sent me from Bolivia cases which were quite uniform, appearing as if made 

 of grey paper; they are conical pointed cases, almost mathematically exact, which hang on rocks. A species 

 very abundant on the fields at Biskra is Amicta quadningularis, of which I have found up to 20 cases on one 

 bush of a herb; this larva builds a very regular tetragonal case of pieces of stalk.s of exactly the same length, 

 which are placed together transversely in a square. Only in very rare instances all materials suitable for 

 covering the cocoon are rejected and — • e. g. bj^ the Australian Thyridopteryx herrichi — the cases made 

 purely of silk, the long-stalked balloons hanging on the trees like fruit. 



Most Psychids are very voracious and not very particular as to their food. Some eat a variety of 

 different plants just as they happen to be handy, and even change from deciduous plants to Conifers. Often 

 dry brown leaves are preferred to the most succulent foliage, and some species appear to eat without distinction 

 any part of a plant from the flower to the almost wooden branch. 



The larvae of the Psychids are very mobile and wander considerable distances. Although the cater- 

 pillar has only the thoracic legs to walk with — the rest of the body is without feet, thin-skinned and almost 

 as .soft as a maggot — ■ they walk fast. Young larvae run nearly as fast as a beetle and the older ones 

 are very adroit climbers. When molested they shrink back and retreat into the case, which they fasten with 

 silk by an exceedingly rapid movement, placing the case over themselves rather than really retreating into it. 

 If one molests them in the case, they use their mouth and fore legs with much power to close the aperture. 

 If thej' are attacked on the trees they go down to near the gi'ound with great rapidity on a silk-thread. In the 

 tree-shaded streets of Montevideo one notices everywhere in February the cases of Oiketicus as large as a thumb 

 hanging dowai from the branches on long threads, and it is there sport for the street-children to collect them 

 and to throw the.se innocent weapons at each other as do our boys in the winter with snowballs. 



When the time for pupation approaches, the case is fastened with tough silk on a base at hand. Tlie 

 ?-cases, which are distinguished in many species from the rj-cases by the more compact build, are usually 

 placed higher, more exposed and more easily accessible to the ^, the more slightly constructed Q-c&i^e is more 

 concealed among the vegetation and hence often nearer the ground, e. g. in Pachytelia minor. The ^ -moths 

 emerge at a regular hour and usually soon begin to fly, some at night, many by day. The more delicate species 

 flutter weakly from stalk to stalk, the large Oiketicus race wildly in great jumps over the fields and prairies. 

 iSometimes a gale surprises them, and after such a ""Pampeiro" which sweeps over the Llanos and Pampas 

 of South America the swamps and puddles are covered with the moths, where the gale has thrown them, in 

 company of masses of the ^ of Hypopta amhigua Hbn., which fall victims to the same force. 



Those cJ(J which escape the not too rare enemies soon find the $? with the help of the organs of 

 scent. The $$ do not leave the case. While the o -pupae are pushed out of the posterior aperture of the case 

 for half their length, the moths escaping and the empty pupal shell remaining in the aperture of the case, the 

 $-larva does not turn round for pupation, the head of the chrysalis remaining directed towards the tightly closed 

 moutli of the case. When the $ is ready for emerging the anal part of the pupal case splits, whereby the genital aper- 

 ture of the ? becomes uncovered. The {J settles on the cocoon and pushes its abdomen into the case copula- 

 tion thus taking place. In order to enable the o to get a good foothold the $-case is provided in some species 

 with a special arrangement for that purpose, the above-mentioned projecting pieces of wood or leaves of some 

 cases, e. g. in Eumeta moddermanni and ignobilis, are said to serve that purpose. 



In spite of the apparently very good cover the larvae of Psychidae are attacked by various kinds of 

 enemies. The Ichneumonidae know very well how to infest them, and many a carniverous enemy goes 

 for them in their cases. They are very mobile withiii the case and when much molested may be induced to 

 leave it altogether, but then the fat soft larvae are quite unprotected and play a poor role. I have often driven 

 such larvae from their covering, left them helpless on the ground for several hours, and then gave them their 



