INVESTIGATION OF LIFE HISTORY. 33 



caterpillars regardless of size. After the body wall of a caterpillar 

 has beeen cut, the Calosoma larva? feed upon the juices and apparently 

 devour a large amount of the fat body of their prey. The entire 

 internal tissues of the caterpillar are seldom eaten, and many speci- 

 mens are injured to such an extent that they eventually die, and thus 

 more caterpillars are prevented from transforming than are actually 

 eaten. The pupae of Lepidoptera, especially those which are destitute 

 of a cocoon, suffer greatly from the inroads of the larvae of this insect. 

 In fact, so far as the gipsy moth is concerned, it is probable that the 

 destruction of the pupae is fully as great as that of the larvae. Of course 

 the pupae are practically unprotected and are in a helpless condition, 

 so that they fall an easy prey to the hungry beetle larvae. Usually the 

 larva forces its mandibles through the gipsy moth pupa, between the 

 segments. The hole is greatly enlarged and the contents of the pupal 

 case are removed before the larva passes on to another pupa. The 

 entrance holes made by the Calosoma larva in the pupa of the gipsy 

 moth are characteristic. (See PL VII.) They are always irregular in 

 outline and sometimes extend nearly the entire length of the pupal 

 case. It is very easy to distinguish these holes from others made by 

 parasites. Fresh gipsy moth pupae are possibly more subject to 

 attack than those from which the adults are more nearly ready to 

 emerge, but there seems to be only a relatively small amount of dis- 

 crimination used by the larva in selecting its victim. Where pupae are 

 massed on the trunks of trees under branches or in any sheltered posi- 

 tion an extremely favorable opportunity is presented for the larvae of 

 this beetle to operate. In fact, in colonies where the beetles are numer- 

 ous it is not uncommon to find one or more of the larvae in every 

 large mass of pupae examined. (See fig. 16.) Usually it is necessary 

 to disturb the pupae, otherwise the beetle larva will be overlooked as 

 it secretes itself beneath the silk and old pupal cases which form the 

 mass and feeds from beneath on the living pupae. Examinations that 

 have been made during the last two years directly in and throughout 

 the territories surrounding many of the beetle colonies which have 

 been liberated in the field, have revealed the presence of large num- 

 bers of pupal cases that have been destroyed by the beetle larvae, 

 although it is seldom possible to find anything like the number of 

 molted skins of the beetle larvae that might be expected from the num- 

 ber of gipsy moth pupae that have been destroyed. In field colonies, 

 the larvae of sycophanta have been found attacking and killing adult 

 females of the gipsy moth. In one case the end of the abdomen of the 

 female was pierced and in spite of the large amount of fine hairs with 

 which the insect is provided and which must be distasteful to such a 

 small predator as a beetle larva, the internal portion of the abdomen 

 including most of the eggs was devoured and of course the death of 

 the moth resulted. 



100834°— Bui. 101—11 3 



