38 Mr. J. O. Westwood on a gregarious 



IX. Description of the Nest of a gregarious sjjecies of But- 

 terjiy from Mexico. By J. O. Westwood, F.Z,.S., Syc. 



[Read February o, 1834.] 



I BEG leave to offer to the notice of the Entomological Society a 

 remarkable example of instinctive economy afforded by the nest of a 

 gregarious species of Butterfly from Mexico, for an opportunity of 

 examining and describing which, I am indebted to Owen Kees, Esq., 

 of Paternoster Row. 



The nest of this insect, which I have figured in Plate VI., is of firm 

 texture, not much unlike very thick parchment, which it also re- 

 sembles in colour. It is about eight inches long, of a somewhat 

 oval form, narrowed at the top for about three inches into a kind of 

 neck, and attached to a slender branch, without the power of swing- 

 ing backwards and forwards, in consequence of being built at the 

 junction of a twig which runs down the neck of the nest. The 

 lower part of the nest is a little produced, and is terminated by a cir- 

 cular orifice about two thirds of an inch in diameter. 



On examining the texture of the nest with a very high-powered 

 lens, it is found to be composed of an infinity of shining and very 

 slender silken lines crossing each other in every direction : from the 

 strength of its texture, therefore, the labour employed in its con- 

 struction must be very great. On the whole, this nest has much 

 the appearance of some of the Paper-making Wasps' nests, such as 

 Vespa chart aria. 



On making a longitudinal incision from the bottom of the nest a 

 remarkable appearance presented itself, not fewer than a hundred 

 chrysalides being attached both to its inner surface, occupying the 

 upper half of the dome of the nest, and to the lower part of the 

 twig descending through its neck. 



The nest is therefore the pendent habitation of the social cater- 

 pillars of a species of butterfly, and is, in fact, the most perfectly 

 formed nest of any Lepidopterous insect yet described. It appears 

 to be a specimen of the nests mentioned by Mr. Hardy in his 

 'Travels in the Interior of Mexico,' lately published (p. 32.). This 

 author, however, neither describes the caterpillar, nor notices the 

 species of butterfly whose constructions excited his observations. 

 He says: " After having ascended for about an hour we came to the 

 region of oaks and other majestically tall trees, the names of which 

 I could not learn. Suspended from their stately branches were innu- 



