398 



HABITATIONS OF INSECTS. 



greatest regularity we often see attached a seemingly super- 

 fluous piece of wood, leaf, or the like.^ 



A larva of one of the aquatic Tipularice lives in cases 

 somewhat similar to those of some PhryganecB. Several of 

 these of a fusiform shape, and brown colour, composed partly 

 of silk, and partly perhaps of fragments of leaves, and inha- 

 bited by a red larva, apparently of a Chironomus, were found 

 by Reaumur upon dead leaves in a pool of water in the Bois 

 de Boulogne.^ 



In concluding this head I may observe, that here might 

 have been described the various abodes which solitary larva? 

 prepare for themselves previous to assuming the pupa, and 

 intended for their protection in that defenceless stage of ex- 

 istence ; but as I shall have occasion again to refer to them 

 in speaking of the larva state of insects, I shall defer their 

 description to that letter, to which they more strictly belong. 



From the next division of the habitations of insects, those 

 formed by solitary perfect insects for their own accommo- 

 dation, I shall select for description only two, both the work 

 of spiders, and alluded to in a former letter ; which indeed, 

 with the exception of the inartificial retreats made by the 

 Grylli, Cicindelce, and a few others, are the only ones properly 

 belonging to it. 



The habitation of one of these ( Cteniza ccBmentaria) is sub- 

 terraneous ; not a mere shallow cavity, but a tube or gallery 

 upwards of two feet in length, and half an inch broad. This 

 tunnel, so vast compared with the size of the insect, it digs 

 by means of its strong jaws in a steep bank of bare clay, so 

 that the rain may readily run off without penetrating to its 

 dwelling. Its next operation is to line the whole from top 

 to bottom with a web of fine silk, which serves the double 

 purpose of preventing the earth that composes the walls from 

 falling in, and, by its connection with the door of the orifice, 



1 For a description of various other habitations of this tribe, and of pecu- 

 liarities in their construction, see M. Pictet's valuable work, Recherches pour 

 servir d VHistoire et d V Anatomic des Phryganides, in which the Linnean genus 

 Phryganea is divided into jseven genera, and the metamorphoses of fifty-two 

 species are described. 



2 Reaum. iii. 179. 



