166 AN ACCOUNT OF BRITISH FLIES. 
insects, and even when stationary, continually move their front legs 
about, using them as feelers. 
This family is distinguished by the following characters: (i.) the 
scutum of the mesothorax undivided ; (ii.) the tibiae and metatarsi_ 
broad, short and compact ; (iii.) ocelli absent, which easily alone are 
sufficient to distinguish it from the Bibionide. The family has basi 
described under the aes names : 
 Tipularie latipennis, Mg. 
Simulides, Zett. 
Simulites, Newn. 
| Simuline, Rond. 
The /arve are aquatic and cylindrical, and live in the stems of © 
water plants. The head is armed with the usual mouth parts and 
two antenne. The larva of S sericeum is slender in the middle, and 
lives in the stems of Phellandrium and of Sium, and has several 
curious appendages as described by Fries. On the head, besides the 
antenne, are two peculiar hairy, flabelliform appendages, and under- 
neath the thorax is figured a tubular process; whilst on the anal 
segment are several curved appendages. 
The pupe are as remarkable as the larvee, they have on each side 
of the front of the sides of the thorax, eight very long filiform 
appendages, arising in pairs analogous to the appendages of the 
pupa of Chironomus; the posterior part of the body is enclosed in 
a semi-oval membranous cocoon attached to the plants and open in 
front. According to Audouin, it appears that the cocoon is formed 
entire by the larva, and afterwards eaten away as far as the thickened 
arch previously formed ; the object of this contrivance being evidently 
to let the water act upon the long filaments of the pupa, which no 
doubt are air-tubes. The imago is hatched beneath the water, 
the tomentum serving to repel it. All the larve seem to be 
aquatic and to live in the stems of plants, where pupation takes 
place. The females are all very objectionable creatures, and follow 
the traveller long distances, frequently attacking him and crawling 
down the neck, and thus getting under the clothes. The males are 
harmless, and often fly in circles in the air; these ‘‘ dances” are very 
curious to watch; they may often be seen in woods in England; 
when at rest, the males may be found on the leaves of trees and on 
flowers. Beech woods seem to be one of their favourite resorts, in 
June and July. According to Zetterstedt,* the common English 
species, S. veptfans, is found even in the snow on the mountain sides 
and summits in Lapponica. 
The geological range extends back to the Purbeck period, where 
* Ins. Lapp., pp. 802, 144. 
Simulide = - 
