NEMATOCERA. 45 
stood. The horny parts consist of a ring with two backwardly-pro- 
jecting processes, with a soft and fleshy labium passing through it. 
There are also two 2-jointed appendages above, the palpi of 
Ratzburg and the antennz of Osten-Sacken. 
On the under side of the larvae we at once notice a curious, horny 
appendage. ‘This is called in America the “ breast-bone,” and in 
England the ‘“‘ anchor-process” (Fig. 10). It is situated at the junc- 
tion of the supernumerary and first thoracic segment. ‘This appendage 
varies in the different species ; the base is buried in the first thoracic 
segment, the elongated stem of the process ends in various forms, 
some being toothed and some serrated. 
Fic. 9.—Zarva (A) and Pupa (B) of a Cectdomyia, greatly enlarged (about 18 
times). 
What is this process and what is its function? Neither of these 
questions can be satisfactorily answered. It is considered by some 
to be homologous to the pseudopods of Chironomous larve. Osten- 
Sacken considers that the fourteenth segment is part of the head. 
This anchor-process, then, might be taken for the mntum, in 
analogy to the horny mentum of Tipularze larve. 
Miss Ormerod considers that it is used as a scraper or digger to 
assist in acquiring the food from the stem.* 
The stigmata, which are horny projections, are normal in number 
* See also Mr, Enock’s opinion, p. 50, Tr. Ent. Soc., 1891. 
