46 Elementary Manual of Zoology. 
worth stocking with fish, a little kerosine-oil poured upon the gurface, 
over which it forms a delicate film, is said to be surprisingly 
effectual in preventing the breeding of mosquitoes. 
The students should examine some mosquito larve and make out 
the breathing organs. They should also notice the structure of the 
antenne in the winged form, both male and female. 
Cecidomyida.—This family comprises a large number of small slen- 
der-bodied species, which lay their eggs in the tissues of plants and 
often produce galls, much in the manner that galls are produced by 
insects of the Hymenopterous family Cynipide. The destructive 
Hessian fly (Cecidomyia destructor, Say.) whose larve are parasitic 
upon wheat-stalks both in America and Europe, belongs to this 
family, while in India there is an allied species (Cectdomyia oryz@) 
which attacks rice in a similar manner. None of the Cecidomyide 
have yet been recorded as destructive in Indian forests, so the 
students will not be expected to know much about them. 
Pulicide.—Fleas lay their eggs in dust and dirt im houses, The 
larve are tiny little hairy grubs, which are to be found in floors of 
badly-kept rooms, where the pupal stage is also spent. The insect is 
said to pass the winter in the larval stage, but in warm weather less 
than a month is required for development from the egg to the imago. 
Burning the matting, cleaning up the floors, with a free use of Persian 
insect powder should be resorted to in houses infested by this pest. 
Vil._—Lepidoptera. 
This order comprises the butterflies and moths, which are exceed- 
ingly numerous in India. They may be defined as insects which pass 
through a well-marked pupal stage, and have scale-covered wings and 
snetorial proboscis in the form of a coiled tube. The proboscis is the 
characteristic feature of the mouth of a typical Lepidopterous insect. 
It is composed of the blades of the maxille, which are mach elongated 
and appressed together, so as to inclose a canal through which fluid can be 
sucked up by the action of the peculiar stomach with which the adult 
insect is furnished, On either side of the proboscis is usually a large 
hairy labial palp, the rest of the mouth parts being rudimentary. 
In the winged stage, Lepidoptera feed largely upon the honey which 
they collect from flowers, they thus become ingore agents for distri- 
buting pollen from flower to flower. 
The larve are worm-like creatures, known as caterpillars, which feed 
upon leaves. For an account of the structure cf a typical caterpillar, see 
the chapter upon the dissection of the mulberry silk-worm, The only 
insects with which caterpillars are liable to be confounded are the 
larvee of saw-flies (Tenthredinida), They can be distinguished from 
