254 Mr. Curtis on the Nests of two Hymenopterous Insects of Brazil, 



undergo their metamorphoses. The only approach to this economy, as far as I 

 can remember, is the nidus formed by the maggots of some of the Ichneumones 

 adsciti*, whose silken cells are placed regularly in rows. The larvae of the 

 saw-flies do not appear to be such skilful workmen as the bees and wasps ; 

 and it is not improbable that insects, when arrived at their perfect or imago 

 state, may possess a greater degree of intelligence or a superior instinct than 

 the grovelling worm, whose business it is to eat until it has arrived at a cer- 

 tain stage, and after various moultings as it increases in stature, when its only 

 care is to find a secure place suited to its transformation into a chrysalis. 

 The irregular forms of the cells will corroborate my remarks ; and their out- 

 line does not appear to be the effect of design, the necessary angles which 

 the pressure of the sides has naturally produced varying in degree and num- 

 ber, and this is the more evident from the partitions being much thicker in 

 some places than in others. In a climate like Brazil, this nest is not con- 

 structed to defend the animals from a low temperature, but it may be to 

 protect them from heavy rains, for it seems to be a covering impervious to 

 wet; the main object, however, is in all probability to prevent the attacks 

 of the parasitic Ichnewnonidce, of which there appear to be vast numbers 

 in South America, some of them with very strong oviducts. The slightly 

 gummy outside covering of the nest would resist a long flexible aculeus, and a 

 short one could not reach the cells through the woolly wall which encloses 

 them, and even if it did, the cell itself at that distance from the Ichneumon 

 could not be penetrated by the delicate ovipositor. It may therefore be con- 

 sidered as one of the innumerable instances of the protection which the Author 

 of Nature provides for the least, and what are improperly termed the most 

 insignificant, of his creatures. 



Having in my collection two species of Schixoctrus which appear to be 

 undescribed, I shall take this opportunity of making their characters known. 



2. SCHIZOCERUS NASICORNIS, Curt. 



Mas niger, abdomine pallide ochraceo apice nigro, alis nebulosis, pedibus 

 fuscis ; femoribus quatuor posticis oehraceis, capite in medio dentato. 



* Mkrogaster alvearius, Curt. Brit. Ent., fol. and pi. 321. 



