C GENERAL SUMMARY OF SCIENTIFIC AND 



nervous system, no circulatory apparatus, and no organs of 

 respiration. In this and other respects he confirms the state- 

 ment of Lubbock, who studied similar stages of Chloeon^ 

 though in a more thorough and philosophical spirit than Joly. 



Some- new observations of Dr. Bertkau on the respiratory 

 organs of the spiders confirm Leuckart's statement that the 

 different aerial organs coexist in these animals, one set of or- 

 gans being lung-like, formed by the modification of tracheae, 

 while the true tracheae also supply the blood with air. He 

 establishes the fact that the spiders {Araneina) have four 

 stigmata, of which the two anterior are situated at the ante- 

 rior part of the abdomen. Tlie two others are placed either 

 immediately behind these or farther back, at the extremity 

 of the abdomen. In this latter case they unite to form a fis- 

 sure in the median line. The first pair of stigmata always 

 leads to " lungs ;" the second to " lungs" (in Mygale)^ or, more 

 frequently, to tracheae. When the second pair of stigmata 

 is anterior, the tracheae to which they correspond always jDre- 

 sent two principal trunks one directed forward, furnishing 

 trachean tubes to the cephalo-thorax {Dy sclera and Segestria)^ 

 while the other passes backw^ard and supplies the abdomen. 

 When the second pair of stigmata is situated at the extrem- 

 ity of the abdomen, and the two trunks must necessarily go 

 forward, it is the external one which corresponds to the jdos- 

 terior trunk of Dysdera and Segestria. 



Another contribution to the subject of phosphorescence in 

 animals is afforded by the studies of Robin and Laboulbene 

 on the phosphorescent organs of the Cucuyo beetle, or fire- 

 fly of Cuba. They examined males alone. It is well known 

 that tw^o luminous eye-like spots occur on the prothorax, and 

 a third on the under side between the thorax and abdomen. 

 Under the transparent spots on the thorax is a mass of fat 

 in connection with tracheae and fine nerves, and the same 

 kind of phosphorescent organ, as the fatty body permeated 

 with nerves and tracheae may be called, was found in the 

 base of the abdomen. On removing these organs from the 

 body of the living insect, they shone brilliantly for some 

 minutes. The authors confirm the statements of Brown and 

 Linnaeus that the insect produces its light at will; and the 

 former ask whether the voluntary freeing of the matter pro- 

 duced relatively to the rest of the substance of the cells'con- 



