190 



THE POPULAR SCIENCE MONTHLY. 



Fig. 2. 



-LiLT-snAPED Tube of Lepto- 

 pelma elongata. 



A third stage in the development of this defensive industry is 

 represented at Fig. 2, which shows the external tube of Lepto- 

 pelma elongata. This is simply a lily-shaped tube of pure white 



spinning-work, rising directly above 

 the burrow, and supported by sur- 

 rounding foliage. The purpose of 

 this structure has not been positive- 

 ly determined. As able a naturalist 

 as A. R. Wallace has conjectured 

 that it may be deceptive in its uses, 

 its resemblance to a flower attract- 

 ing to it insects, which are thus 

 preyed upon by the proprietor. 

 Such elevated objects are certainly 

 apt to attract insects, who are dis- 

 posed to alight upon them without 

 regard to their promise of provid- 

 ing food. But I am inclined to be- 

 lieve that Leptopelma's silken lily 

 serves as a watch-tower from which 

 she can observe the approach of enemies and make good her 

 escape in time. Moreover, I believe that it is possible for her to 

 pull together the sides of the sheeted turret and thus erect a bar- 

 rier between herself and some of her feebler pursuers. 



Another form of defensive industry is presented at Fig. 3, which 

 is the exterior part of the turret tube of Dolichoscaptus inops (Si- 

 mon). This is about an inch in height, 

 and is composed of mingled chippage 

 and mud, a sort of debris of chopped 

 straw and soil. 



A still further stage is shown at 

 Fig. 4, which represents a columnar 

 turret of Dolichoscaptus latastei, sev- 

 eral inches high. This resembles the 

 tower of the preceding species, but adds 

 thereto a hinged covering after the 

 manner of a trap-door. This turret is 

 also composed of chippage and debris of various sorts gathered 

 from the neighborhood, and is supported upon the surrounding 

 foliage, which in the drawing is a plant of Lavandula dentata. 

 All the uses to which such an elevated structure can be put are 

 served by this ingenious structure, and, in addition, the trap-door 

 is manifestly intended to defend the inmate from the assaults of 

 enemies. 



We come now to the trap-door nests of Nemesia meridionalis, 

 and other species making traps of the wafer type, as so fully de- 



FlG. 3 



Tukret of DolicJioscaptvs 

 inops. (Natural size.) 



