38 Dr. D. Kcilin on the Larvce &c. of 



thoracic and eiglit abdominal), 'and one pair of metathoracic 

 non-functional spiracles connected -with the main tracheal 

 truiilvs by means of simple chitinous bands. 



All the functional spiracles, except the last abdominal, 

 are circular, with nnraerous trema surrounding a central 

 chitinous plate which corresponds to the cork-shaped scar 

 (" Bouchon cicatriciel ") of the spiracles of Trichocera, 

 Tipulid or Bibionid larvae. The prothoracic spiracle 

 (fig. 21) is much larger in size than any of the first seven 

 ])airs of abdominal spiracles (fig. 18). 



The posterior abdominal spiracles (fig. 20, s.p.^, which 

 are situated on the dorsal projections of the Inst abdo- 

 minal segment, are elongated and spine-shaped. The surface 

 of their external scar {s.c.) is covered with very small 

 chitinous hooks. 



Alimentary canal (fig. 16). The very short pharynx 

 is enclosed in the larval head. It is followed by a short 

 oesophagus {o.e.) which enters the proventriculus {pr.). Two 

 long lateral coeca {ft.c.) arise from the anterior part of 

 the midgut, just behind the proventriculus and, directed 

 backwards, are tightly applied to the lateral sides of it. 

 The midgut (niff.) is in the form of a stiaight cylindrical 

 tube. The four Malpighian tubes (M.) arise separate!}' at 

 the junction of the mid- and hind-gut. Tiiese four tubes 

 lie in the [)Osterior part of the bodv and surround the hind- 



The salivary glands {s.ff.) are tubular and extend a small 

 distance behind the jiosterior end of the anterior cceca. 



The pupa (PI. IV. fig. 24) is 8 mm. in length, comi)letely 

 free from the larval skin, and brown in colour. The head 

 is much recurved on the ventral side, and the thorax, which 

 projects forward, bears a pair of prothoracic resjiiratory 

 horns (^>.//.). The legs of the pupa are not su|)erposed as 

 is often the case in dipterous pupse, but lie in the same 

 plane. Each abdominal segment bears dorsally a row of 

 short spines. The last segment (PL IV. fig. 25) is furnished 

 with five pairs of hooks curved dorsally. 



III. Symmerus annuluta, Meigen. 



All our knowledge of the larvae of Symmerus was con- 

 tained in a short sentence of Winnertz (1863, p. 671), Avho 

 bred " one female from a larva which lived in a decomposed 

 fungus on Carpinus hetulus.'' 



During the month of May of this year Mr. Edwards in- 



