116 
A noplieles Maculipennis 
zugewandten Flache des ausseren Lappens 1 festgeklebt, oftmals bis 10 
und mehr auf einem Querschnitte und zeichnen sich durch grosse 
Tinctionsfahigkeit vor sonstigen aus. Grosse Oenocytben sind auch 
in Gruppen zu vier bis fiinf segmentweise im Abdomen angeordnet, 
liegen aber eben so wie die kleinen auf der Innenseite des die 
Leibeshohle auskleidenden Fettkorperlappens befestigt.” 
Oenocytes have been discovered in a number of dipterous larvae, 
and it is extremely probable that they are of general occurrence 
throughout the order. In Ghironomus they have been described by 
Wielowiejski (p. 515) and Miall and Hammond (1900, pp. 40—42). 
The large oenocytes are restricted to the abdomen, and consist of a 
group of five very large cells on either side in the first eight segments. 
The fifth cell in each group lies in front of the cluster of four cells and, 
moreover, differs from them in containing two nuclei, viz. a large 
central one and a small one situated at the periphery. The small 
oenocytes are very numerous and are found towards the ventral surface 
of the metathoracic and abdominal segments, just beneath the inte¬ 
gument. Oenocytes are also present in the larvae of Tipula oleracea 
(Wielowiejski), Phalacrocera replicata (Miall and Shelford, 1897, 
pp. 352), Simulium (Vaney, 1202) and other Nemocera. 
Among the Brachycera they appear to have been very little studied. 
Wielowiejski (p. 520) states that in this group of Diptera they present 
the characters of the large oenocytes of Cliironomus, and differ chiefly in 
being more numerous, and in having a more intimate connection with 
branches of the tracheae. They have been carefully studied, however, 
by Pantel (1898, p. 210) in the Tachinid, Thrixion halidayanum. In 
the larva of this fly they are collected into a ventral and a lateral group 
on each side, in the seven posterior segmeuts of the body. Each group 
contains as a rule 3-6 cells, which are soldered together into a “chapelet.” 
Pantel puts forward the suggestion that possibly one of the two groups 
in Thrixion is the homologue of the binucleated cell in Ghironomus and 
that the latter is in reality the rudiment of a colony of uninucleate 
cells. 
Among the Pupipara, according to Berlese (1901, p. 145) in 
Melopliagus ovinus, the oenocytes are disposed in metameric groups in 
the larva but, at the commencement of nymphosis, they multiply and 
are found in numbers among the cells of the fat-body, and subse¬ 
quently disappear at the time when the Malpighian tubes are developing. 
1 i.e. the “Fettkorperlappens.” 
