78 
HOW TO COLLECT 
The habits of the larvse belonging to the families constituting the 
Acalypterate Muscidce are too diversified to be dealt with in detail. 
Some are to be found in ordure ; others attack the stems of grasses 
and cereals ; while the larvse of others again (e.g. Trypetidce) live in 
fruits, in seed-heads, in galls on the stems, or mine in the leaves of 
various plants. 
How to Preserve Larvae. 
Specimens of Dipterous larvae will always be valuable, whenever it 
is possible to breed out some of them so as to determine the fly to 
which they belong. Unless, however, the perfect insect is known, it 
is rarely possible to do more than to determine the family to which 
a larva belongs. Larvae for preservation should be killed by 
immersion for a moment or two in boiling water, and should then be 
placed in weak spirit (two-thirds spirit and one-third water) ; after 
being allowed to remain in this for two or three weeks until 
thoroughly hardened, they can be transferred to stronger spirit. 
The larvae of each species must of course be kept separate, and 
should be put up in a small corked glass-tube full of spirit, the 
necessary particulars, with, if possible, a reference to pinned specimens 
of the perfect insect, being written in pencil on a scrap of paper and 
placed inside. 
Notes on Habits, etc. 
Very little is yet known as to the habits of Diptera in general, so 
that notes on the habits, distribution, seasonal occurrence, relative 
frequency, etc., of particular species will always be of great value 
and interest.* Particular attention should be paid to the habits of 
blood-sucking species and others of economic importance; in this 
connection it may be noted that information is greatly needed as to 
the habits and reproduction of Tsetse-flies (Glossina), especially as 
to whether the bites of all species of Glossina are equally fatal to 
domestic animals. A good look-out should also be kept for cases 
of mimicry between Diptera and Hymenoptera, which will be found 
♦ For special points in connection with Mosquitoes as to which information 
is desired, see " How to collect Mosquitoes." 
