June, 1893. CANNIBALISM AMONG INSECTS. _ 445 



All the caterpillars belonging to a particular group or family 

 showed a preference for the flesh of their own relations. They 

 devoured one another in considerable numbers, rarely feeding on the 

 plants suitable for their nourishment. The caterpillars of the family 

 of the Bombyces devoured their kin with skin and hair, and they 

 went as far as to break through the cocoons in order to finish with 

 the chrysalis within. 



In a similar manner, the caterpillars of the Noctuids behaved 

 with those of their own kind and with those of the Bombyces. 



The caterpillars of these latter attacked also those of the former 

 without any exception. The most voracious of the Noctuids was the 

 caterpillar of Heliothis armiger ; a single one of these consumed, in 

 twenty-four hours, six or seven other caterpillars. 



The caterpillar of the well-known butterfly, Pyrameis carye, is 

 also a carnivorous cannibal, but with moderation, preferring always 

 fresh plants to meat, while the others, and chiefly those of the 

 Noctuinae, after having tasted the flesh of their own kin, would no 

 longer touch vegetable food. 



I explain this particular character of the Patagonian caterpillars 

 in the following manner. During the principal part of the summer in 

 Patagonia there is considerable heat and dryness which causes the 

 vegetation quickly to be parched up and scarce. When this happens 

 the caterpillars lose their means of subsistence, but, in order that 

 some may survive, the struggle for existence has taught them another 

 means of subsistence, that is, the flesh of their own kind. Once this 

 instinct has been inherited, the descendants will use it whenever an 

 occasion presents itself, and, in many instances, even when there is no 

 lack of vegetable food. In some cases it is necessity which produces the 

 habit ; in others, inheritance which leads up to it ; thus neAv biological 

 characters are formed. 



Of other herbivorous insects cannibalism has been noticed in 

 crickets in confinement. The first notice of this strange taste we owe 

 to Sir W. Brodie (Canad. Entom. vol. xxiii., p. 137, i8gi), whose 

 observation has been recently confirmed by Mr. Philip Laurent 

 (Entom. Neii's, vol. ii., p. 180, 1891). 



In an assemblage of many crickets kept for certain observations 

 in a rearing drawer, or box (caja de herborizacion), the numbers 

 diminished from day to day ; at last only one — not a little fattened — 

 remained by the side of the remains of his former companions. 



Hitherto cannibalism among the crickets has been noticed only 

 among captives, but I am now enabled to state that, under certain 

 conditions, cannibalism is present among some Orthoptera in the 

 free state, at all events among the locusts. 



In the summer of 1883, in which the excessive heat and drought 

 had brought about the nearly entire disappearance of the vegetation 

 in a good part of the country, and more particularly in the broken 

 country of the Banda Oriental, I had occasion to make a journey 



