PARASITES FREE DURING THEIR WHOLE LIFE. 123 



all kinds of animal matter in a state of decomposition. 

 It is even said that tliese insects, deceived by the 

 smell of the Arum flower, will lay their eggs on the 

 pistil. The name of Myasis has been given to the pre- 

 sence of these larvae in a womid. 



Every one knows that bats are often literally covered 

 with vermin. Among the many parasites which attack 

 these little animals we find, besides the acaridse, a 

 Pteroptus of great agility, which seems, as it were, to 

 swim among the fur, and looks like a little spider or a 

 microscopic crab. There are but few bats on which we 

 do not find some of these, and we have sometimes seen 

 them in such abundance, that it was impossible to 

 touch a single hair without disturbing them. This 

 species is usually called Pteroptus vespertilio7tis. It is 

 constantly in motion, and glides among the fur like a 

 mole in a sandy soil. 



Together with these Pteropti lives a parasite of 

 gigantic size, which insinuates itself among the fur with 

 equal dexterity, and bears the name of Nycteribia. This 

 has long claws like a spider, and plunges deeply into 

 the fur. These Nycteribi£e are found only on bats. They 

 are often associated on these animals with fleas and 

 mites. Mr. Westwood has written a monograph upon 

 them. Mons. Plateau, our colleague, has quite recently 

 described a new species in the *' Bulletins de 1' Academic 

 de Belgique." 



Among the insects justly dreaded by man, and which 

 follow him everywhere, is found one of the Hemiptera, 

 known by every one under the name of bed-bug {Cimex 

 lectularia). It is said that this insect was unknown in 

 the capital of Great Britain before the fire of London 



