46 HOUSE, GARDEN, AND FIELD 



glowworm by another light than its own I mean the 

 lamp of science. 1 



Let me now put and answer as well as present know- 

 ledge permits, three questions about the glowworm. 



QUESTION i. What is the worm that glows ? 



It is a female beetle, about half an inch long, and 

 peculiar in having the wings and wing- covers totally 

 deficient, so that it resembles a larva ; the body is long, 

 narrow, and flattened ; the legs are short ; the head is 

 retractile, being withdrawn upon occasion into the fore 

 part of the thorax ; the eyes are small ; and the jaws are 

 those of a predatory insect. It is probable that the adult 

 insect feeds little ; indeed there is reason to believe that 

 the adult male does not feed at all. Some naturalists 

 have found the female feeding on plants, but fuller evi- 

 dence is still to be desired. The larva on the other hand 

 is carnivorous, and devours small mollusks, either dead or 

 alive. The glowworm keeps close by day, but shows 

 herself by night, often climbing up stalks or the branches 

 of shrubs in order that her light may be as little obstructed 

 as possible. 



QUESTION 2. How is the light of the glowworm produced ? 



It is emitted from the under side of the abdomen, espe- 

 cially from the sixth and seventh segments, and can be 

 traced to a yellowish substance, which is freely supplied 

 with branching air-tubes, and shines through the trans- 

 parent skin. Though the light looks so steady, it is really 

 intermittent, consisting of flashes in close succession, 

 eighty or a hundred in the minute. It has been much 

 debated whether the glowworm can extinguish her light at 

 pleasure or not. When alarmed, she certainly causes the 

 light to disappear, and late in the evening she ceases to 

 shine. But on close examination it will be found that 



1 One of the most important of recent researches on the glowworm by 

 Bongardt will be found in Zeits.f. iviss. Zool., 1903. 



