1911.] NATURAL SCIENCES OF PHILADELPHIA. 407 



Thus it is seen that before any operation the average time is five 

 seconds, after removal of palps 5.2 seconds, with palps and maxillae 

 both removed it is 6 seconds. Therefore after considering the 14 per 

 cent, increase of response on the second day, it is evident that the 

 palps have but little to do with the olfactory sense. Moreover the 

 maxillae seem to play a slightly more important role but this may 

 probably be due to the effect of the operation, because the spiders 

 were slightly less active after the removal of the maxilla 1 . 



Judging from the structure of the lyriform organs, we must conclude 

 that they have some kind of a sensory function. Sight, touch, taste 

 and hearing may be eliminated at once for the following reasons. 

 The eyes serve for the sense of sight. Spiders are no more tactile 

 near or directly on these organs than elsewhere. The taste organs 

 would have to be associated with the mouth. Since it is evident that 

 spiders cannot hear, then these organs could not have an auditory 

 function. Now, there are left for consideration the humidity, olfactory 

 and temperature senses. No experiments were performed to deter- 

 mine the humidity sense, but in my opinion spiders do not have such 

 a sense. 



In order to ascertain whether the lyriform organs have an olfactory 

 sense fifteen large adult Lycosa lepida, fresh from the fields and all 

 normal in every way, were selected for the varnishing operations. Here 

 as in other cases each spider was fed and watered each day. These 

 fifteen Lycosas were tested carefully with the five oils to see if they 

 had the correct olfactory perception. Late in the afternoon all the 

 lyriform organs (single slits not included) on the legs, palps, chelicera, 

 mouth parts and sternum were carefully varnished with yellow com- 

 mercial vaseline by placing a tiny daub of this substance on each 

 organ. Great precaution was taken not to use too much vaseline 

 and not to get any of it on the lung-books. Immediately after being 

 varnished the spiders began to clean themselves and removed prac- 

 tically all the vaseline from the chelicera, mouth parts and tarsi of 

 the legs and palps. After one day's time the remaining vaseline did 

 not spread very much, but after four or five days it formed a thin 

 coating over all the legs, cephalothorax and sometimes over the abdo- 

 men. When the vaseline covered the lung-books and trachea? the 

 spiders died in a short time. Most of these araneads, however, lived 

 at least four or five days after such an operation, while some lived 

 fifteen to twenty days, and a few survived almost the entire summer. 

 In these latter the vaseline had all evaporated and the arachnids 

 again responded normally to odors. After the operation the spiders 



