vii MYCETOPHILIDAE 463 



unimaculata forms its slimy tracks; T 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 2 

 the so-called Xew Zealand Glow-worm is the larva of JJulcto- 

 pltilii 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 Ccroplatus mastersi is also luminous. 

 Another very exceptional larva is that of E]_>i<-i/j>tn scatophora ; 

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

 remarkable structure of the dorsal parts of the b< >dy ; 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 Perri* was 

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

 this unusually formed larva. The larva of ITycetul'm jxilliji,-* 

 (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 Hkyjjkt'.s, a fly of 

 quite another family, and the My<-?tul>i,i larva so closely resembles 

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

 This anomalous larva gives rise, like the exceptional larva of 

 El'K'i/lrf", to an ordinary Mycetophilid fly. 3 



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

 - Trims. Xc/r Zcdmiit lust, xxiii. 1890, p. 48. 



3 Osten Sacken, Berlin. cnt.Zeitschr. xxxvii. 1892, p. 442; and Ferris, Ann. Soc. 

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



