192 SUMMARY OF CUKKENT KESEAKCHES RELATING TO 



known species (the greatly reduced abdomen, long metasternum, and 

 consequent far-back position of the hind legs, and the extreme slender- 

 ness of the tarsi). It is also peculiar in the great size of the clul> of 

 the antenna, a feature, of course, distinctive of the males, and also in 

 a still more interesting peculiarity, in all probability peculiar to that sex, 

 namely, the cleft inner claw of the front foot. The absence of the 

 female is another significant point of agreement with Fhmiognatha and 

 Adopus, of which only a single female specimen has yet been recorded. 

 It is probable that in in all the genera the females are sluggish, and 

 differ from the males in habit. 



Study of Silver-Fish.* — J. W. Cornwall has made a study of a 

 silver-fish insect, supposed to be Le/mma mccharina, which has done 

 considerable damage to books, papers, and pictures in the Pasteur 

 Institute of Southern India. The female insect deposits six to ten eggs 

 at a time in crevices. The eggs are glistening white, 1 • 5 mm. by 1 mm., 

 sometimes asymmetrical. Hatching occurs in forty-five to sixty days at 

 laboratory temperature (is" to 'lO'^ C), and the young insect resembles 

 the adult in essential features. The first ecdysis occurs soon after 

 hatching, and is followed by several others. Maturity is reached in 

 about two years. 



The insects are lucifugous. Their progression is usually a rapid 

 run with frequent sudden pauses. There seems to be a slight prepon- 

 derance of females. The antennae and setae are important as sensory 

 structures. 



The creatures can live for l;-J8 days without food ; the mean in the 

 starving experiments was eighty-eight days. They eat paper, cloth and 

 the like. How they obtain proteid food in their usual surroundings is 

 not obvious. They devour their dead neighbours. They do not tolerate 

 moist cold or dry heat. Nothing but concentrated vapours and gases 

 will destroy adults. The external and internal structure is described 

 with care, and an account is given of two distinct Gregarines found 

 parasitic in the gut. 



5 Arachnida. 



Antillean Spiders.f — Frank E. Lutz has considered the distribu- 

 tion of the West Indian spiders, and has come to the conclusion that 

 there has been considerable movement between the individual islands 

 and also between the mainland and the islands, especially at the two 

 ends of the island chain, even in recent times when the islands were 

 separate from each other and from the mainland. It is therefore un- 

 necessary to suppose that land connexions ever existed. Ancient forms 

 have had a longer time to reach the islands than the more recent ones ; 

 they were adapted to a tropical environment, and the insular character 

 of the area has protected them, hence a large part of the fauna consists 

 of relicts, as is shown by the relationships with South Africa, Mada- 

 gascar, Ceylon, Australia, and the Philippines. Recent forms are now 

 mingling with and replacing the older forms. 



* Indian Journ. Med. Research, iii. (1915) pp. 116-31 (6 pis.) 

 t Ann. New York Acad. Sci., xxvi. (1915) pp. 71-148 (8 figs.). 



