Gi (March, 



grainp ; those from Ratisbon more cylimlrical, f line broad, and 3 lines long, less 

 flat, rounded only on the hind end, and compressed tliere, flourj-white on the surface. 

 In spring on licliens." 



I have found th.at cases from Portland are of very delicate struc- 

 ture, and, after they become empty, very soon get the ends more or 

 less rubbed off, and also tend to assume a cylindrical form ; the same 

 result takes place if they are not very carefully handled ; and I think 

 it not impossible that the difference between the two forms of cases 

 mentioned by von Heinemann may be accounted for by the manipu- 

 lation they received from the collector, or by their being tenanted or 

 empty when collected. In the Portland specimens there is no difference 

 between the ends, and they are used indifferently by the larva, as in 

 the case of T. pellionella. It is, in fact, very nimble in turning round 

 inside its case, and will sometimes draw its head in at one end, and 

 almost directly put it out at the other, when stopped by a paint-brush. 



The little claspers, of which it makes no use in walking when 

 taken out of its case, are doubtless employed in holding on inside to 

 the delicate silken lining. If taken out of its case and left on the 

 lichen-covered stone, it will, in the course of a day or two, construct a 

 new case for itself, like most case-bearing larvae. 



The Portland cases, like the Grerman, are made of lichen and 

 sand, or small stony particles, which must in some way be obtained 

 from the surface of the very hard Portland stone. As I find that 

 these particles are present in the lichen when brushed off the rock, I 

 can only infer that the surface of the rock is slightly disintegrated by 

 the roots of the lichen, and utilized by the larva. Such a case must 

 be a great protection against the jaws of many insects. 



Probably this larva, like T. j^ellioneUa, makes a case as soon as it 

 is hatched. It lives upon the under-side of stones, and feeds entirely 

 on the fine microscopic lichen which covers them. It is sometimes to 

 be found on the sides of the stones, but I have never seen it on the 

 top. Its favourite haunt is amongst the loose piles of stones so 

 abundant at Portland; where it is generally distributed, though scarce. 



I have this winter two larvae, found last spring with others which 

 spun up and emerged last summer, which proves that the larva some- 

 times, and perhaps always, feeds for two years before pupating ; a 

 fact which is also indicated by the occasional occurrence of very small 

 larvae at the same time as full-grown ones, the former being very bard 

 to detect, and, therefore, probably often passed over. 



Lord Walsingham has very kindly sent mo specimens of Tinea 



