Studies on Tipulidae, 173 



5. Early stages of Ctenophora sensu stricto and of 

 Xiphiira compared. 



■A general account of the larvae of Tipida and Ctenophora will 

 be foimd in the Monographs on K Am. Diptera, IV, p. 4 — 7. My 

 purpose here in to justify the final Separation of JClphura from 

 Ctenophora by a comparison of their larvae and pupae. 



The european Ctenophorae, as we have seen, form two natural 

 groups: ^iphura on one siele, and Ctenophora sensu stricto plus 

 Dictenidia on the other. Larvae and pupae of both groups show 

 very marked differences. 



The larvae of Ctenophora s. s. and Dictenidia belong to the 

 same type of structure ; whether there is any difference between them 

 that may be deemed of generic importance I have been unable to 

 ascertain. Like many larvae of Tipulidae, they have, at the anal 

 end of the body a pair of pointed, fleshy lobes, and several smaller 

 fleshy protuberances; their skin is tough and opaque, the opacity 

 being due to a dense microscopic, appressed pubescence. Since the 

 rather rough figures of the transformations of the larvae of this 

 group by Reaumur (Mem. V, Tab. 1, f. 11—16), and De Geer (Vol. VI, 

 Tab. 25) no good figure of them has been published, except in the 

 work of Weyenbergh : Beitr. Z. anat. d. hemicephalen Dipteren-Larven ; 

 Haarlem 1872. Only Mr. Weyenbergh was mistaken in the Identification 

 of bis species ; the larva figured on Tab. I , f. 1 is that of a Cteno- 

 phora sensu stricto, probably O. pectinicornis, and n o t of -STip/mra 

 ri(ßcornis, as the Explanation of the plate has it (1. c, p. 55 and 

 passim). 



The larva of J^iphura has no fleshy lobes at the end of the 

 body; its stigma-bearing discs are protected by soft, fleshy swellings, 

 surrounding them ; its skin, very differert from the tough skin of the 

 larva of Dict. himacidata for instance, is exceedingly delicate and 

 transparent; the anatomy of the larva can be studied through it. 

 The feason for this difference of structure seems to lie in the mode 

 of life of the larvae. I have repeatedly found the larva of Dict. hi- 

 macidata in the wet detritus under the bark of decaying trees; the 

 appressed microscopic pubescence is a character common to many 

 larvae living in damp situations, The larva of J^iphura lives in 

 the decaying wood itself, and burrows in it; its mandibles for this 

 reason are much stronger; and its Stigmata are protected against 

 the sawdust around them by the peculiar arrangement described 

 by Mr. Hermann (Mitth. d. Münchener Ver. f. Ent. 1880, p. 146), 



