Vol. xxiii] ENTOMOLOGICAL NEWS 399 



Fragments on North American Insects — L 



By A. A. GiRAULT, Nelson (Cairns), North Queensland. 



1. Protective Attitudes of the Caterpillars of Datana ministra 

 Drury (Lepid.). 



The peculiar attitude of the individuals in colonies of young 

 larvae of this species when at rest was noticed at Blacksburg, 

 Virginia, August 25, 1902; the head plus the thorax are held 

 curved rigidly over the back, while the three distal segments 

 of the abdomen are held in the same manner, but in the oppo- 

 site direction. Even when in motion, the distal abdominal 

 segments are still upcurved. When individuals in a colony 

 are disturbed, with great suddenness, they wriggle from the 

 leaf and hang suspended by a thread of silk. Disturb the 

 whole colony and they all fall together. Older larvae form 

 nearly a complete hoop when slightly disturbed. 



The significance of the resting attitude above noted becomes 

 evident when we read the following : On September 2, 1902, 

 a badly infested linden tree was shaken violently, dislodging 

 the caterpillars which fell into the grass below; soon a number 

 of tachina flies were noticed buzzing about without apparent 

 aim or resting sharp-eyed upon near-by blades of grass. These 

 had already discovered the caterpillars which were crawling 

 and wriggling about in the grass (if they had not known of 

 them for some time and were waiting about for a chance to 

 attack them). Every now and then, one of the parasites darted 

 suddenly at one of the larvae and attempted to deposit an egg 

 on its body, not at any point on its surface but on the thorax 

 just behind the head. If unsuccessful, the fly would alight and 

 follow the larva on foot, keeping as nearly behind the head 

 as possible and running along in a peculiar sidelong manner, 

 reminding one of the totally different, yet extremely similar be- 

 havior of a courting rooster. It thus followed the crawling 

 caterpillar, over and under, twisting in and out, the blade of 

 grass, flying short leaps when necessary, until at a favorable 

 opportunity the fly would dart at the thoracic region, leave an 

 egg and dart away. These attempts were not always success- 

 ful; for the pursued caterpillars acted in a manner altogether 

 incomprehensible without attributing it to a sense of fear. 



