174 AN ACCOUNT OF BRITISH FLIES. 
clinging feet. There are also a pair of pediform appendages figured 
on the last segment, analogous to those in fig. 37 of Chironomus 
flumosus, and also four branchial appendages on the same segment, 
with two tufts of hairs in addition. These larve grow rapidly, so that 
within six or seven days they are four to five times their original length. 
After the third moult the larva is one third of an inch long, its head 
becomes smaller, and its feet elongated; the skin acquires a very 
delicate rose colour, caused by the development of the pupal skin 
beneath. The movements of the larva gradually lessen and eventu- 
ally cease ; it then casts its skin, and the pupal stage is reached. 
The pupa is three m. long, with long head, described by Grumm 
as not unlike that of a cat, with 9-jointed abdomen, and the six legs 
on the thorax, and bent around the wing cases. The abdomen is 
covered by many small paired hairs and longer single sete. The 
sides of the abdomen exhibit long dark brown bands, which terminate 
in the penultimate segment in a small bunch of claw-like processes. 
On the last but one segment are two apertures, and between and 
below them a third, the anal orifice. There are also two groups of 
delicate hairs on the last segment. The thorax is dilated dorsally 
into a shield covering the head above ; at the sides of the thorax the 
wing-cases are visible. Prominent pyriform eyes are also seen, 
between which lie the antennz. Above the head are two thick fila- 
ments ; these are no doubt branchiz (resembling those seen in the 
pupa of Corethra plumicornis). No stigmata are of course seen in 
these aquatic forms. Such is briefly the structure of the Chironomus 
larva and pupa observed by Grumm, in which asexual reproduction 
was observed to take place. We remember in the case of the 
Cecidomyide, the asexual generations were produced by the Cecid 
larvee {p. 42), and that the larve producing the asexual generations 
eventually themselves turned to perfect insects, But in the case of 
the Chironomide we find things very different ; it is not the larva 
Fic. 38.—Eggs of Chironomus. 
that has the asexual reproduction, but the pupa; neither are living 
young (maggots or pupz) produced but ova, whereas in Cecidomyia 
living larvae were produced. The two holes above the anus 
described in the pupa are the orifices through which the eggs are 
