INSECT LIFE UNDERGROUND. 



L. O. HOWARD, PH. D., 

 Entomologist U. S. Department of Agriculture, and Curator Department of Insects, U. S. 



National Museum. 



THERE is an old German child's 

 story of a little girl who being 

 told that if she could find a 

 place to hide her first silver 

 piece where no eye could see her, and 

 then dance round it three times, she 

 would have her wish. She sought 

 everywhere for such a place, but always 

 some bird or squirrel or mouse or in- 

 sect was near by, and even when she 

 dug beneath the ground, there too 

 were little crawling creatures watch- 

 ing her. 



It may be said that this story was 

 meant to show that animal life is found 

 almost everywhere, and certainly be- 

 neath the surface of the ground there 

 are hundreds of kinds of insects work- 

 ing steadily away at their different 

 occupations; for whatever disagreeable 

 things you maj^ find to say about in- 

 sects, you can never justly call them 

 lazy. The scriptures recognized this 

 fact in the well-known command to 

 the sluggard, and the old nursery rhyme 

 about the " busy bee" emphasizes the 

 same characteristic. 



The truest underground insects are 

 those which pass their entire lives be- 

 neath the surface of the earth; which 

 are born there, live and grow and die 

 without seeing the light of day. Such, 

 for example, are the true cave insects, 

 a number of forms of which are found 

 in the great caverns in different parts 

 of the world. Some of these insects 

 feed upon the vegetable molds and low 

 forms of plant life found in caves; 

 others feed on dead animal matter and 

 still others upon living insects. Nearly 

 all are of pale colors and are blind or 

 nearly so, for they have no use for eyes 

 in the darkness. All are supposed to 

 be descendants of above-ground forms, 

 which through many generations of 

 life in the darkness have lost their 

 color and their power of sight. The 

 genealogy of these true cave forms 

 maybe guessed at with some certainty, 

 for we know insects which are only 

 partly transformed in structure from 



above-ground forms to true cave 

 species. Such are certain beetles which 

 live in the catacombs of Paris, and cer- 

 tain other insects which have been 

 found in the old and deep burrows of 

 the land tortoise in Florida. 



But we do not have to go to caves to 

 find many other true underground in- 

 sects. Rich, loose soil abounds in such 

 creatures which live upon the decaying 

 vegetation (soil humus or vegetable 

 mold) or upon one another. The most 

 abundant in numbers of individuals are 

 the little spring-tails or bristle-tails, 

 minute creatures seldom more than a 

 sixteenth of an inch in length and 

 which frequently swarm in the ground 

 in such numbers that the earth seems 

 fairly alive. These little creatures are 

 by no means confined to the surface 

 soil, but have been found in great 

 armies at a depth of six feet or more 

 in stiff clay, which they have pene- 

 trated by following the deeper rootlets 

 of trees. Certain of these little insects 

 have also become so accustomed to 

 this lightless life that they have lost 

 their eyes. 



Other true underground insects are 

 found in the nests of ants, where they 

 fill many different functions. They 

 may be grouped, however as follows: 

 I. Species which are fed by the ants 

 and from which the ants derive a bene- 

 fit by eating a certain secretion of the 

 ii^ect. 2. Species which are treated 

 with indifference by the ants and which 

 feed upon the bodies of dead ants and 

 other animal and vegetable debris to be 

 found in ants' nests. The ants are cer- 

 tainly not hostile to these insects and 

 evidently gain some unknown benefit 

 from their presence. 3. Species which 

 live among the ants for the purpose of 

 killing and feeding upon them. The 

 first true ants' nest insect was only dis- 

 covered and studied at the beginning 

 of this century, but since that time 

 hundreds of other species have been 

 found, and a mere catalogue of their 

 names fills a book of over 200 pages. 



