APTERA 



195 



T^i, tb"f B! 



prostemmatic organ of young; C, of 

 adult. ( After Laboulbene. ) 



congregate in masses on the surface of the rock pools. This 



Anurida can endure prolonged immersion; but both the ob- 



servers we are quoting say that it is, when submerged, usually 



completely covered with a coat 



of air so that the water does not 



touch it. The little creature 



can, however, it would appear, 



subsist for some time in the 



pools of salt water, even when 



it is not surrounded by its 



customary protecting envelope 



of the more congenial element. 



Its food is said, on very slender 



evidence, to consist of the re- 



mains of small marine animals, 



Slich as MolluSCS. We repro- 

 i c -T , -., , , 



duce some 01 Laboulbene s 

 figures (Fig. 100) ; the under-surface shows at a the divided pap- 

 illa of the ventral tube ; B, C represent the peculiar prostemmatic 

 organ, alluded to on p. 193, in its mature and immature states. 



Very little information exists as to the life-history of the 

 Aptera ; as for their food, it is generally considered to consist of 

 refuse vegetable or animal matter. It is usual to say that they 

 are completely destitute of metamorphosis, but Templeton says of 

 Lepisma niveo-fasciata that " the young differ so much from the 

 mature Insect that I took them at first for a distinct species ; the 

 thoracic plates are proportionately less broad, and the first is 

 devoid of the white marginal band." As regards the moults, it 

 would appear that in this, as in so many other points, great 

 diversity prevails, Grassi stating that in Campodea there is a 

 single fragmentary casting of the skin ; and Sommer informing us 

 that in Macrotoma plumbed the moults are not only numerous, 

 but continue, after the creature has attained its full growth, 

 throughout life. 



A very marked feature of the Aptera is their intolerance of a 

 dry atmosphere. Although Campodea, can exist under very 

 diverse conditions, it dies very soon after being placed in a dry 

 closed tube*; and the same susceptibility appears to be shared by 

 all the other members of the Order, though it is not so extreme 

 in all ; possibly it may be due to some peculiarity in the structure 



