436 Prof. J. O. Westwood's 



the leaf, it re-ascends, as must be supposed to be the case 

 with the Lepidopterous larv^ mentioned recently by 

 Mr, Fritz Miiller in a communication to " Nature," 

 January 18th, 1877, which is sufficiently curious to 

 warrant its republication, and which is as follows : — 



" I have lately become acquainted with an interesting 

 case of commensalism in two caterpillars. The larger, 

 with red head, protected by long branching stinging hairs 

 or thorns, lives on mulberry and other trees. Like other 

 caterpillars protected from enemies by odours, stinging 

 hairs or otherwise, it sits on the upper side of the leaves 

 and is light coloured, the head red, the hairs white. 

 Across its back, between its thorns, there sits a small 

 blackish caterpillar protecting itself by the thorns of the 

 large companion. I took off the small caterpillar from 

 the large one, but it soon occupied again the same place. 

 In order to take a photograph of it the larger caterpillar 

 was ansssthetised with ether; it recovered again some- 

 what, but after two days it died. The smaller caterpillar 

 has now left its place and taken refuge on another cater- 

 pillar in the same box ; on this it sits somewhat further 

 forward, on the base of the abdomen. In its former post 

 the place where the small caterpillar sits looks pale, as if 

 it had been scoured. The small caterpillar from above 

 eats small holes in the leaf on which the larger one is 

 sitting. As far as I know no similar case has hitherto 

 been observed." 



The caterpillar upon which the pmaUer one resides 

 belongs to the genus Doratifera (Limacodes), as appears 

 from his figure, but the author is silent as to the genus or 

 even order of the smaller caterpillar ; and were it not that 

 he calls it a caterpillar (confining the name apparently to 

 the Lepidoptera), and that he says it descends and eats 

 holes in the leaf, we might infer that it was a real external 

 parasite, especially as he notes a difference in the appear- 

 ance of that part of the larger caterpiUar on which the 

 smaller one had sat. 



Two other instances of more doubtful parasitism in 

 Lepidoptera have fallen under my notice. I obtained 

 from the collection of the late J. Curtis two small brown 

 Tineideous moths about the size of Depressaria Populi, 

 to one of which was attached a note in the handwriting 

 of Mr. Curtis, "living on the Bradypus tridactylus, I 

 believe." I also obtained from one of the boxes of insects 

 collected by Mr. Bates on the Amazon, two small moths. 



