70 ON PSYCHOPTERA PALUDOSA. 



be seen through it, especially the fat-bodies, which are conspicuous 

 by their brilliant white colour and great size. 



They lie on the mud, covered by a mere film of water, the 

 respiratory tail floating on the surface, and appear almost motion- 

 less, their only means of movement, indeed, being the successive 

 contraction of the segments of the body, aided by the slightly 

 thickened ring, with which each is furnished. That they pass 

 much of their life buried in the mud, however, appears from the 

 fact that I have frequently observed its exposed surface in their 

 haunts to be pitted with holes, and that whenever this is the case 

 a plentiful supply of these larvae is sure to be obtained by digging 

 up a handful with a trowel. It is remarkable that the first 

 occasion on which I found the pupa was as early as March, 

 whereas Lyonet states that with him they underwent their trans- 

 formation in June. I have myself found them from March until 

 as late even as July. Probably Lyonet's observations were made 

 upon a few specimens kept for the purpose, and which were all 

 exposed to one uniform condition. 



The head of the larva, see Plate IX., Fig. 5, is hard and horny, 

 in striking contrast to the softness of the rest of the body. Lyonet 

 describes it as furnished with a pair of appendages similar (as I 

 gather from his figures) to those which I believe to be antennse 

 in the larva of Taiiypus inaculatus.'^'^ I have not been able to 

 verify this, the two minute projections seen in my drawing of the 

 head being, I think, the maxillary palpi. A pair of minute black 

 spots on the upper surface, as in Tanypus^ represents the eyes. 

 The most interesting portion of the organisation of this insect is 

 the respiratory system. Like all other dipterous larvae it is 

 furnished with a pair of conspicuous tracheal trunks, extending the 

 whole length of the body, and prolonged in this instance into the 

 filamentous tail, which is simply the terminal segment very much 

 attenuated and prolonged (see Fig. 2). At the base of this 

 segment two styliform appendages occur. 



The trachse in this part of their course are simple tubes, 

 having the usual spiral fibre in their walls, and much convoluted 

 near the base of the tail. I do not think these tubes have any 



* See "Journal of the Postal Microscopical Society," June, 1882. 



