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tormentors. They frequent woody places and hang from plants 
ready to attach themselves to any animal that may chance to 
pass. Taking a firm hold with the legs the insect implants the 
rostrum into the skin, where it remains firmly held in place by 
the retrograde teeth. So firm is it that if one tries to pull the 
insect off the head will be broken off and remain in the wound. 
The female gorges herself with blood, often swelling to ten times 
her normal size (sometimes as big as an olive). When satiated 
she withdraws her rostrum and falls to the ground, where under 
a stone or bit of wood she lays a heap of eggs and then dies. 
Hatching lasts from 15 to 20 days. The male is brown, the 
female orange coloured, except when full of blood, when she 
becomes purplish. These insects have a special breathing plate 
behind the last two legs. 
(b) The next family, Trombidiidae, furnishes one parasite of 
special interest, Trombidium holosericeum, or red mite, or harvest 
bug. The mature insect lives on grass land and in woods. The 
female lays her eggs in July, and the larva which emerges will 
attach itself to any mammal. Moles and rabbits suffer most, 
but many dogs and many men suffer also, and cats are even 
attacked. The specimens shown were taken from my own dog 
after she had been playing in the garden. They set up a terrible 
itching by implanting the rostrum in the skin and sucking. The 
insect is a bright orange red, and when first seen is about the 
size of the eye of a small needle. The completion of its develop 
ment does not take place on its host, whom it leaves when 
satiated. 
(c) Sarcoptidae. This is one of the most important families 
and is the one which furnishes us with the cause of true mange. 
This was named by the Greeks psora or itch, and by the Romans 
scabies (from scabere, to scratch), and is known in England by 
many names, such as itch, scald, yuek, and mange. _ Its history 
is common both to man and animals. In Leviticus we read that 
that most expert sanitarian and M.O.H., Moses, excluded mangy 
animals from sacrifice as unclean. In Hannibal’s campaign 
against the Gauls both men and horses suffered from it. But its 
nature was first discovered by an Arab physician, Avenzoar, who 
lived in the 12th Century. The insect was only determined 
finally to be a sarcopt in 1834 by a Corsican, Renneir. 
Some idea of the power the disease has of spreading is 
formed when it is seen that each female lays about fifteen eggs— 
ten female and five male. These in fifteen days are mature and 
begin to reproduce their species, so that at this rate from one 
single female in 90 days (about three months) may be produced 
1,000,000 females and 500,000 males ! 
The Sarcoptidae are sub-divided into Sarcoptes, Peoroptes, 
and Symbiotes, and of each there are many varieties. 
