NOTK ON THE OCCURRENCE OE TRAPDOOR 

 CATERPILLARS AT ALICEDALE. 



Bv Frank CRUDi::N. 



(Plate 2.) 



Dnrino^ the last three years, while searching for trapdoor 

 spiders' nests in the veld round Alicedale, I often found tubes 

 with \ery small round trapdoors. At first I assumed that these 

 wert- also constructed by spiders, but on opening several I foimd 

 the occupant to be, in each case, a caterpillar. As it was just 

 possible that these had taken possession of nests that had been 

 vacated by spiders, I placed half-a-dozen caterpillars beside holes 

 bored for them in soft ground in a box. They at once entered 

 the holes, tail first. l"he holes were soon lined, and in each case 

 a lid was made. 



The fliameter of the largest lids seldom exceeds 6 in.m. 

 Thev are usually concave on the outside, and fit very closely into 

 the mouths of the ttibes. The nests are difficult to detect. They 

 are often found in soft ground under the shade of bushes, and 

 in spots with a sparse growth of moss or grass. Moss is some- 

 times found on the outer surface of the lid, but whether the 

 caterpillar attaches it, or it grows there naturally, I have not 

 yet been able to ascertain. The tubes are frequently very tor- 

 tuous, and measure in length from 12 to 16 cm. They are 

 usually, if not always, slightly constricted just below the lid. 



I must have opened scores of nests in the hope of finding 

 tlie occui)ant in the ])Ui)a stage, but without success imtil the 

 latter part of April and the beginning of May this year (1916), 

 when I was fortunate in finding three or four, which were handed 

 over to Mr. J. Hewitt, of the Albany Museum. 



.■\s I liad dug out each nest in a mass of eartii, 1 returned to 

 each tube, from the lower end, its rightful owner. It was curious 

 to note ( though it seems quite natural when one thinks of it ) 

 how the ]mpx wriggled up the tubes owing (o (he fiexibility of 

 the lower ].arts of their cases. 



In a few hour> the moths emerged from the tul)es, the lids 

 being pushed open, and the em])ty pupa; cases left sticking in the 

 constricted parts already referred to. One moth, whose pupa 

 case was not returned to the tube, was unable to emerge until 

 it was placed between two layers of cotton-wool ])ressed down 

 just tirmly enough to ki-cp the case in ])osition while the moth 

 was pulling itself out. 



These nests are \ ery abundant, and at the time mentioned 

 above (when the bulk of the moths emerge) they can be seen 

 in great numbers with the em])t)' pu]);e cases ])rojecting from 

 tlieir mouths. 



The moth has not yet been fully identified: it is referable 

 to the family I lepialida? (fide Mr. C. j. Swierstra). Similar 

 trai)door cater])illars were taken at Port .Alfred several years ago 

 by Mr. I'. .'~^. .'^alisljury. who found them in abundance in the 

 thick bush fringing tiie Kowie River. They have also been found 

 on the flats a<ljoining the Cradock road, Cjrahamstown. 



