84 [April, 



NOTE ON TEEBMOBIA FURNOEUM, EOVELLT. 

 BY DB. D. SHARP, M.A., T.E.S. 



About two years ago Mr. "W. Bateson, of St. John's College, 

 brought me two specimens of a Lepisma from a bakehouse here, which 

 I thought were different from L. saccharina, and which reminded me 

 of Oudemans' figure of TTiermopJiila furnorum which T had recently 

 seen ; the specimens, however, were not adult, and were in bad con- 

 dition, so that I could only say that I thought it was a form that had 

 not previously been recognised in England, and that I should like to 

 see other examples. No more, however, have been forthcoming until 

 three days ago, when a large number of specimens of various sizes 

 were brought to me, having been caught in a bakehouse here. These 

 specimens quite confirm Mr. McLachlan's opinion expressed in the 

 last number of this Magazine, that we have in England this interesting 

 Thysanuran, which must be called TJiermohia furnorum at present. 

 The mottling with coloured scales is very characteristic, but varies 

 greatly, as the scales are shed with great facility, though, according to 

 Oudemans, they are renewed at the next moult. 



Mr. McLachlan's paper refers to all the sources of information 

 as to the insect so far as I am aware, and Oudemans' paper is so very 

 good, though brief, that casual observation does not allow me to add 

 anything to it. There is, however, one point in the external anatomy 

 of TJiermohia and Lepisma of a very unusual nature, and which, so far 

 as I know, has been alluded to only by Oudemans in Bijd. tot de 

 Dierkunde, Afl. 16, p. 157, and by him only in a few words. This is 

 the peculiar folds or plates formed by the three sterna. In these 

 Thysanura all the coxae are large, and form a shield to the under- 

 surface of the body, as they do in the common cockroach, but instead 

 of being quite free as in the cockroaches, they are, in these Thysanura, 

 controlled by a large flap of the sternum ; this flap has only a small 

 point of connection with the extremely delicate integument of the 

 body ; its outer surface is quite covered with scales, and its margins 

 ciliated, so that it forms a beautiful object under the microscope. 

 The only structures that I can recall at all similar to it in arrangement 

 are the peculiar abdominal plates of Haliplidce. It would, however, 

 be possible to suggest an analogy with the patagia of Lepidoptera. In 

 all these cases the structure consists of a flap with a comparatively 

 small attachment to the body. I believe the use of these peculiar 

 structures in all the three cases I have mentioned is unknown, 



Cambridge : March 8th, 1894. 



[I shall be glad of further information as to the distribution of Thermohia 

 furnorum in this country or on the Continent. — K.. McLachlan]. 



