38 _ Dr. D. Keilin on the Larve dc. of 
thoracic and eight abdominal), and one pair of metathoracie 
non-functional spiracles connected with the main tracheal 
trunks by means of simple chitinous bands, 
All the functional spiracles, except the last abdominal, 
are circular, with numerous trema surrounding a central 
chitinous plate which corresponds to the cork-shaped scar 
(“ Bouchon  cicatriciel”) of the spiracles of Trichocera, 
Tipulid or Bibionid Jarve. The prothoracic spiracle 
(fig. 21) is much larger in size than any of the first seven 
pairs of abdominal spiracles (fig. 18). 
The posterior abdominal spiracles (fig. 20, s.p.), which 
are situated on the dorsal projections of the last 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 
cesophagus (0.e.) which enters the proventriculus (pr.). ‘T'wo 
long lateral cceca (a.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 (mg.) is in the form of a straight eylindrical 
tube. The four Malpighian tubes (2/.) arise separately at 
the junction of the mid- and hind-gut. These four tubes 
lie in the posterior part of the body and surround the hind- 
gut. 
The salivary glands (s.g.) are tubular and extend a small 
distance behind tie posterior end of the anterior coca. 
The pupa (PI. LV. fig. 24) is 8 mm. in length, completely 
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 prothoracie respiratory 
horns (p.h.). The legs of the pupa are not superposed as 
is often the case in dipterous pupe, 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 annulata, Meigen. 
All our knowledge of the larvee of Symmerus was con- 
tained in a short sentence of Winnertz (1863, p. 671), who 
bred “ one female from a larva which lived in a decomposed 
fungus on Carpinus betulus.” 
During the month of May of this year Mr. Edwards in- 
