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 antennce of Osten-Sacken. 



On the under side of the larvs we at once notice a curious, horny 

 appendage. This is called in America the " breast-bone," and in 

 England the "anchor-process" (Fig. lo). 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. 



B. 



Fig. 9. — Larva (A) and Pupa (B) of a Cecidomyia, 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 homologoi'.s to the pseudopods of CJiiroiwmoiis larvae. Osten- 

 Sacken considers that the fourteenth segment is part of the head. 

 This anchor-process, then, might be taken for the nicntum, in 

 analogy to the horny mentum of Tipularse larvae. 



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. Knock's opinion, p. 50, Tr. Ent. Soc, 1S91. 



