LYCtENA II., III. 15 



itcelf to the utmost to reach its prey. The sting was just about to strike the 

 extreme end of the hirva, when the ant made a dash at the tly, which flew 

 away, and so long as I stood there, at least five minutes, did not return. 

 The larva had been quiet all this time, its head buried in a hower bud, liut 

 the moment the ant rushed and the Hy lied it seemed to become aware of the 

 danger, and thrashed about the end of its body in great alarm. The ant 

 saved the larva, and it is certain that Ichneumons would in no case get an 

 oj^portunity to sting so lung as such a vigilant guard was about. It seems to 

 me that the advantage is mutual between the larvae and ants, and that the 

 former know their protectors, and take satisfaction in rewarding them. This 

 was the only occasion which has fallen under my observation in which the actual 

 attempt to sting was defeated; but on IGth June, 1881, I saw several larvae and 

 several ants on a stem of Rattle-weed, about which one of these flies was liover- 

 ing. It came very near to one larva, but an ant, not standing upon the latter, 

 ran at the fly, which then departed. On 20th June, 1879, I saw another fly 

 creeping along a stem on which was a half-grown larva, but no ant. The fly 

 moved up, put one leg on the larva, rested an instant, turned round, and when 

 I thought it was about to give the fatal thrust it hesitated, and after standing 

 quiet more than two minutes flew away. I concluded that either the larva was 

 too 3'oung for the purpose of the fly, or that the latter discovered that it had 

 already been parasitized. I have introduced hou.^e flies to larvae in tubes, and 

 there was no alarm, nor was any notice taken, though the flies buzzed about and 

 even stood on the larva?. 



Whether all other species of LycoDua are supplied with the special organs above 

 described I cannot say. Very little observation seems to have been made on this 

 point. The books have rarely spoken of either the organs, or of ants attending 

 the larva;, and in most cases the observations seem to have been isolated, and the 

 object for which the ants attended the larva; undiscovered ; or if the organs were 

 observed, the connection with the ants was not. In Newman's British Butter- 

 flies, Lond. 1871, p. 125, I find this sentence quoted from Prof. Zeller : '• I could 

 not perceive that these caterpillars (L. Medon) had a cone capable of Ijeing pro- 

 truded, like that which we find in L. Cori/don, and which the ants are so fond of 

 licking." Guenee, as has been seen, discovered the tubes and the organ on 11, 

 and saw the fluid exude therefrom, but could not conjecture its object. 



Dr. Hagen called mv attention to the followini>; mention in Stett. Ent. Zeit., 

 XXYI. p. 115, 1815 : •• Mr. C. Plotz says that he found caterpillars of L. Argus 

 on Call una vulgaris. Was puzzled at seeing that every caterpillar had an ant 

 standing on its back, and saw about forty larva? near ant hills, the ants always on 

 the larvas, standing or walking, and apparently the caterpillars were in no way 



