498 



On Cotylosoma dipneusticum, W.-M. 



LTX. — Observations on the supposed Semiaquatic Phasmid, 

 Cotylosoma dipneusticum, W.-M. By Charles O. 

 Waterhouse. 



In the 'Annals' for 1878 

 Mason called attention to a 

 species of Phasmidfe in the 

 British Museum, to which he 

 gave the name Cotylosoma 

 dipneusticum, and which he 

 suggests may be " modified 

 for an aquatic life ; for it 

 breathes not only in the or- 

 dinary fashion amongst in- 

 sects by means of tracheae 

 opening by stigmata on the 

 exterior of the body, but also 

 by the structures known as 

 tracheal gills," &c. 



Dr. David Sharp having 

 recently asked me questions 

 about this insect, I think it 

 well to figure it and to call 

 attention to the following 

 facts : — 



1. So far as I am aware, 

 nothing is known of the 

 habits of this species. It may 

 or may not be aquatic. 



2. The specimen is a dried 

 one, and I think Wood- 

 Mason in the sentence above 

 quoted assumes too much. 

 There is nothing in the form 

 of the lateral plates of the 

 metathorax to show definitely 

 that they are "tracheal gills," 

 although I would not, on the 

 other hand, say that they are 

 not. I notice, however, that 

 an allied Brazilian insect — 

 Prisopus phacellus — has very 

 similar plates, one on each 

 side of the insertion of the 

 anterior tibia. For the 



the late Mr. Wood- 



Cofi/losomn dipneusticum. 

 (I. Knee-joint of Prisopus phacellus. 



