MYCETOrHILIDAE 463 



uniniaculata forms its slimy tracks ; -^ it stretches its head to one 



side, fixes the tip of a drop of the viscous matter from its 



mouth to the surface of the substance over which it is to 



progress, bends its head under itself so as to affix the matter to 



the lower face of its own body ; then stretches its head to the 



other side and repeats the operation, thus forming a track on 



which it glides, or perhaps, as the mucus completely envelops 



its body, we should rather call it a tunnel through which the 



maggot slips along. According to the description of Hudson ^ 



the so-called New Zealand Glow-worm is the larva of Boleto- 



j)li%la luminosa ; it forms webs in dark ravines, along which it 



glides, giving a considerable amount of light from the peculiarly 



formed terminal segment of the body. This larva is figured as 



consisting of about twenty segments. The pupa is provided 



with a very long, curiously-branched dorsal structure : the fly 



issuing from the pupa is strongly luminous, though no use can 



be discovered for the property either in it or in the larva. The 



larva of the Australian Ceroplatus mastersi is also luminous. 



Another very exceptional larva is that of Epicypta scatoph or a ; 



it is of short, thick form, like Cecidomyiid larvae, and has a very 



remarkable structure of the dorsal parts of the body ; by means of 



this its excrement, which is of a peculiar nature, is spread out and 



forms a case for enveloping and sheltering the larva. Ultimately 



the larval case is converted into a cocoon for pupation. This larva 



is so different from that of other Mycetophilidae, that Ferris w^as 



at first unable to believe that the fly he reared really came from 



this unusually formed larva. The larva of MycetoMa 'po-^lw^^ 



(Fig. 221) offers a still more remarkable phenomenon, inasmuch 



as it is amphipneustic instead of peripneustic (that is to say, it 



has a pair of stigmata at the termination of the body and a pair 



on the first thoracic segment instead of the lateral series of pairs 



we have described as normal in Mycetophilidae). This larva lives 



in company with the amphipneustic larva of EhyjyJms, a fly of 



quite another family, and the MycetoMa larva so closely resembles 



that of the Rhyphus, that it is difficult to distinguish the two. 



This anomalous larva gives rise, like the exceptional larva of 



Epicypta, to an ordinary Mycetophilid fly.^ 



1 Ann. Soc. cnt. France (2) vii. 1849, p. 346. 

 ^ Trans. Kew Zealand Inst, xxiii. 1890, p. 48. 



^ Osten Sacken, Berlin, ent. Zcitschr. xxxvii. 1892, p. 442; and Penis, Ami. Soc. 

 ent. France (2) vii. 1849, p. 202. 



