98 



THE YOUNG NATUKALIST. 



on walls, are all attacked by this little creature. Fortunately, there is 

 only one species known in England, this is said to have been imported from 

 America, where Dr. Hagen says they have " half-a-dozen species." I trust 

 that none of the other five species will ever be found in England, and that 

 their loyalty to the land of the free will be a sufficient excuse for their remaining 

 at home. L. saccharina is of a silvery grey colour, and is about one-third 

 of an inch in length. The eyes are in two clusters of twelve in each, and at 

 the sides of the head, very near the thorax. It would be a wonder if we had 

 not got Saccharina seeing that it is such a cosmopolitan, for its destructiveness 

 has been recorded not only from the chief cities of Europe, but also from 

 India, Australia, and Jamacia. 



We have, however, two very closely allied species, these we may consider 

 as friends, seeing they feed on decaying vegetable matter — one inland and 

 the other on the sea-shore. The former {Machilis polyoda), is very common 

 in the woods and old lanes around Plymouth. I should like to know if it 

 occurs plentifully in other counties ; it is mottled-brown, and is commonly 

 known by the name of " Spring-tail." The other is Machilis maritima, this 

 species may be often seen running over the rocks close to high- water mark, 

 in colour it is very much like the other, but with an addition of a slight tinge 

 of olive-green ; this species always carries its antennae pointing forward, 

 while polypoda, which is always running about in woods among the fallen 

 leaves, &c. is, perforce, obliged to carry them over its back. 



The scales of the three species are often used as test objects for high power 

 of the microscope. 



OBNOXIOUS AND INJURIOUS INSECTS. 



By JOSEPH CHAPPELL. 

 (Continued from page 95J 



Pulex irritans, the common flea, is considered to be a wingless and 

 aberrant form of dipteron. The female deposits about a dozen white and 

 mixed eggs in a cluster, the larvae have no feet and resemble little worms; 

 they are very lively, rolling themselves into a circle or spirally, and crawl 

 with a serpentine motion ; they are said to feed in neglected beds, and in the 

 crevices of bedroom floors, under carpets, &c. They are full-fed in about a 

 fortnight, when they enclose themselves in a small silk cocoon, and in about 

 twelve or fourteen days change to the perfect insect. If any person is 



