38 Timehri, 



and having found one is informed of the presence and position of a 

 caterpillar within the cane probably by the vibrations set up by its 

 gnawing and movements. She then endeavours to reach it by thrusting 

 her long ovipositor up into the tunnel or boring If the caterpil.hr be 

 beneath a leaf-sheath wdiich it has nearly gnawed through, she gets at it 

 by piercing the leaf-sheath at the spot where the caterpillar is eating. 

 The Iphiaulax larva is dirty or yellow white, and feeds externally on the 

 catdrpillar, at first just gently imbibing its juices, but when full growth 

 is approaching practically eating it up. Near the last stages growth 

 is so rapid that it can double its size in a single night. If it be detached 

 from a caterpillar, it appears usually to be unable to regain its hold, with 

 the result that it perishes. In the tunnel of the caterpillar it constructs 

 a white or dirty white cocoon in which it pupates, the perfect insect 

 appearing about 12 to 14 days after. The cocoon is cylindrical, flat at 

 the ends. 



The female Iphiaulax seems to endeavour to select for attack full- 

 grown or nearly full-grown caterpillars. She certainly, however, makes 

 mistakes sometimes, and attacks caterpillars that are not big enough to 

 afford sufficient nutriment to her larva? which therefore perish. We can 

 excuse her, since she does not see the caterpillar she attacks. I have 

 come across instances where larvae have finished off their caterpillar, but 

 to be faced with death by starvation. 



A caterpillar with an Iphiaulax larva upon it is always observed to 

 be in a state of coma or paralysis no matter if the larva be so young as 

 evidently to have been not long disclosed from the egg. In fact the 

 larva being an external feeder would run the risk of being fatally bruised 

 against the walls of the tunnel by a violent movement of the caterpillar, 

 or of being jerked off its back to perish ultimately of starvation, were 

 not the caterpillar thrown into a state of virtual quiescence. I have not 

 determined satisfactorily the manner in which the paralyzed condition is 

 produced. Can it be by some act of the adult female Iphiaulax at the time 

 she lays her egg ? It would hardly seem so, as the Braconids are not 

 poison-secreting hymenoptera. Even assuming that it results from some 

 act of the female at the time of oviposition, the paralyzed state does not 

 perhaps occur immediately, for on two occasions while breeding Diatrcea 

 moths from caterpillars collected from the field I got out an Iphiaulax, 

 and the caterpillars which gave the parasite had at first been quite as lively 

 as their unparasitized fellows. Indeed, I was quite unaware that any of the 

 caterpillars was parasitized, as none, when collected, had parasite larvae 

 upon them. It seems more likely that the paralyzed condition is caused 

 by some act of the parasite larva? in their earliest stages. In every 

 instance where I have found young larvae they have always been affixed 

 to the thorax at a point immediately behind the head, and paralysis of 

 the caterpillar probably results from the larvae attacking, as a first act 

 after hatching from the egg, its nervous system.* 



* See Note 3 at end of article. 



