or THE GLOwwoEM (lamptris noctiluca). 49 



I believe, is uot usual. I have always found my specimens in 

 confinement attached as stated to the exposed roots or stems of 

 grass, whence the larvae, when hatched, are most likely to find 

 their prey near to them, and where they are constantly in a damp 

 place, and in a situation in which all their requirements are best 

 supplied. 



Supposed Liiminositi/ of the Eggs. 



It has frequently been stated that the eggs are luminous, but of 

 the truth of this there is considerable doubt (Eogerson, Miu'ray, 

 Tiedemaun) : they certainly are slightly effulgent soon after they 

 are deposited, but this, I consider, is due rather to the matter with 

 which they are covered when extruded, than to any inherent pro- 

 perty of their own. With the view of ascertaining the truth of 

 the statement, I have examined the ova both within and without 

 the body. In the female which had died unimpregnated on the 

 tenth day after capture, the ovaries were filled with ova, and when 

 placed in water before removal from the body aj)peared to emit a 

 greenish light ; after three hours' immersion they still appeared, 

 when the specimen was carried into a dark room, to give out a 

 very faint greenish light ; but when they had been standing a few 

 hours longer in the water, no light was perceptible from them : the 

 light appeared to have been due to what was transmitted through 

 them from the segments. I then opened the body of a female that 

 was still living, but which had deposited a large proportion of her 

 eggs ; and on carrying the specimen into a dark room, the remain- 

 ing ova appeared to be luminous, like the preceding ; the specimen 

 was then immersed still living in water, and the ova appeared to 

 be more luminous than before. The entire ovaries containing the 

 ova were next removed jfrom the body beneath water, placed in a 

 separate vessel, and carried into a dark room, but no light was 

 then emitted by them. They were as opake as those of other 

 iasects ; so that the light which they appeared to give out before 

 removal from the body, was due in reality to that of the light- 

 giving segments, being transmitted through them. The segments 

 themselves, after the eggs were removed, still emitted light very 

 powerfully, although immersed in water, and continued to do so for 

 nearly five hours, while the insect lived, and almost as brightly as 

 when the insect is uninjiu-ed. In a third instance, which was 

 examined at the same time as the preceding, I found the ovaries, 

 when opened in the air, fidl of ova, but these were not luminous. 

 On placing the insect in water, the eggs then appeared to give 



LINN. PEOC. — ZOOLOGY. 4 



