306 INSECTS AND MAN 



in America to provide constant meals of living larvae to 

 over six thousand hungry beetles is, in itself, a tall order 

 and one not lightly undertaken, for Calosoma and its larvae 

 feed day and night, and, being of a fastidious, cannibalistic 

 nature, will not accept raw meat or any other substitute 

 for their living food. Consider the care lavished on the 

 females during oviposition, the countless experiments to 

 learn everything in the beetle's life-history that could 

 possibly be turned to good account by man, and the 

 hundred and one little details that always arise during 

 such an undertaking, and some small idea of the magnitude 

 of the work will be gleaned. 



Now let us turn our attention for a moment to the work 

 of this little beetle in the field, and learn how wonderfully 

 it is adapted by habit to wage war on the larvae of moths 

 in general and the gipsy and brown-tail moths in particular. 

 The moth larvae we know infest trees, and the larvae of 

 Calosoma, unlike the grubs of many beetles, are active and 

 addicted to tree-climbing in search of food. This trait in 

 itself is of incalculable value, for this little friend of man 

 is of practical utility both in the larval and adult stages 

 of its life. Day and night these voracious youngsters 

 attack caterpillars, seizing them from the side or in the 

 middle of the back, or, if the caterpillars are hairy, between 

 the segments, where the skin is smooth. Even the newly 

 hatched larvae are able, by means of their strong mandibles, 

 to master caterpillars, regardless of size. After making an 

 incision in the body wall, the Calosoma larva feeds on the 

 juices of its prey and consumes the greater part of its fat. 

 The moth pupae are not exempt from attack, vulnerable 

 spots between the segments are selected, characteristic 

 holes, irregular in outline and extending nearly the whole 

 length of the chrysalis, are made and the contents eaten. 

 And this brings us face to face with a most extraordinary 

 and useful trait the beetle larvae prefer the female pupae. 

 In an experiment at the State insectary it was found that, 



