DIPTERA. 47 
Many species of gnat, known as mosquitoes, are to be found in 
‘America. All travellers speak of the sufferings endured by a 
stranger in that country, from the bites of these insects. One can 
only preserve oneself from these cruel enemies during sleep by 
hanging gauze, called a mosquito curtain, round the bed. Mos- 
quito curtains are not only necessary in America. During the 
hot season, in Spain, throughout the whole of Italy, and a part of 
the south of France, it is necessary to hang these curtains round 
the bed, if one wishes to obtain any sleep: it is also a necessary 
‘precaution not to have a light in one’s bedchamber, as the sight 
of it at once attracts these dangerous companions, whose buzzing 
and stinging prevent any possibility of repose during the whole 
night. Such is our advice to people who travel in the above- 
mentioned countries. 
The Yipulide have a narrow, elongated abdomen, and long 
and slight limbs. The head is round, and the eyes, which are 
compound, are, especially in the males, very large. The wings, 
which are long and narrow, are sometimes held wide apart, 
sometimes horizontally, and sometimes bent so as to form, as it 
were, aroof. The balancers are naked and elongated ; the abdomen 
long, cylindrical, and often terminating in a club in the male, and 
in a point in the female. The antenne, which are longer than 
the head, are generally composed of from fourteen to sixteen 
joints, and are sometimes in the form of a comb or saw, some- 
times furnished with hair, in form of plumes, bunches, or in a 
whorl. The larve live on plants, in the fields, in gardens, and 
sometimes in woods. The perfect insects, at first sight, resemble 
enats, but are without a trunk, or rather their trunk is extremely 
short, terminating in two large lips, and the sucker is composed 
of two fibres only.* The larger species of Tipule, which are 
* The genus Cecidomyia, which belongs to this family, presents the most extraor- 
dinary instance of agamo-genesis, or reproduction without fertilisation by another 
individual, at present known among insects. Until lately it was almost an axiom 
with naturalists that no sect was capable of reproduction until it had attained its 
adult or perfect state. Several continental observers, some of them without any 
knowledge of the others’ discoveries, have found that the /arve of some of the species 
of this genus reproduce larvee resembling themselves in every respect ; and what is 
still more strange, these laryze live in a free state within the parent larva, feeding 
upon its tissues, and causing its ultimate destruction. 
A very interesting article on this subject will be found in the ‘‘ Popular Serene 
