The Habits of various Insects 1 ). 



(A letter to Ch. Darwin.) 



I delayed answering your kind letter of January i till I should have had 

 an opportunity of examining once more some nests of leaf-cutting ants, to 

 which you had directed my attention. In the meantime I received Belt's "Nica- 

 ragua," which I have read with extraordinary interest, and for which I must 

 express to you my hearty thanks. 



I was much surprised to learn from Mr. Belt's book how closely the far- 

 distant province of Chontales resembles by its vegetation and animal life our 

 own of Sta. Catharina. I am thus enabled fully to appreciate the exactness of 

 many of his statements; he is an excellent observer, and most of his theories 

 are very seducing. As to leaf-cutting ants, I have always held the same view 

 which is proposed by Mr. Belt, viz. that they feed upon the fungus growing on 

 the leaves they carry into their nests, though I had not yet examined their 

 stomachs. Now I find that the contents of the stomach are colourless, showing 

 under the microscope some minute globules, probably the spores of the fungus. 

 I could find no trace of vegetable tissue which might have been derived from 

 the leaves they gather; and this, I think, confirms Mr. Belt's hypothesis. Here, 

 as in Nicaragua, the Cercropise are always inhabited by ants, but, I think, by only 

 a single species. I have cut down hundreds of them and never missed the ants. 

 I wonder that it had never occurred to me that the trees are protected by the 

 ants; but there can be no doubt that this is really the case, for young plants of 

 Cercopise, not yet inhabited by ants, are often attacked by herbivorous insects. 



A few days ago I caught on the flower of a Vernonia a female moth be- 

 longing to the Glaucopidae, of which family there are here numerous species. 

 When I seized it by the wings nearly the whole body became suddenly envel- 

 oped in a large cloud of snow-white wool, which came out of a sort of pouch 

 on the ventral side of the abdomen, and consisted of very thin flexuous hairs 

 i 2 mm. long, three, four, or five of which used to proceed from the same 

 point. I preserved the moth alive for some time, and as often as I seized her 

 by the wings, by inflating the abdomen, a large naked membrane became visible, 



i) Nature 1874. Vol. X. p. 102, 103. 



