NO. 9 OLFACTORY SENSE OF INSECTS McINDOO 49 



on the legs were covered with the heeswax-vasehne mixture. These 

 females now appeared normal in all respects other than their slowness 

 in responding- to odors. When tested, they gave a reaction time of 

 7.94 seconds, which is more than twice the reaction time obtained 

 before using the glue and vaseline. 



The wings of 25 males of Camponotus were pulled ofif. These 

 ants appeared normal in all respects except their slowness in respond- 

 ing to odors. When tested, they gave a reaction time of 3.49 seconds, 

 which is one and a fourth times the reaction time of unmutilated 

 males. Only 12 per cent of the pores on the wings were left intact. 



The wings of 21 workers of Vcspula maculata were pulled ofif. 

 These hornets appeared normal in all respects other than their slow- 

 ness in responding to odors. When tested with the three essential 

 oils, they gave a reaction time of 6.35 seconds, which is almost three 

 times the reaction time for sister hornets with wings intact. Only 

 22 per cent of the pores on the wings were left intact. 



OLFACTORY ORGANS ON THE APPENDAGES AND STERNUM OF 



SPIDERS 



In 1878 Bertkau noticed some slitlike cuticular organs on the 

 .legs of spiders. Since that date five other observers, including the 

 present writer, have studied these structures. They are called lyri- 

 form organs on account of their shape. 



The author (1911) made a special study of the morphology and 

 physiology of the lyriform organs of spiders. He used in his studies 

 39 species representing 27 of the 38 families. These organs in 

 spiders exist both as isolated slits and as groups containing several 

 slits, and their position is relatively constant. The groups are located 

 at the distal end of each joint of the legs, pedipalpi, chelicera (mouth 

 parts), pedicle, and spinnerets. They exist on both sides of the fore- 

 going appendages and as a rule each joint of the legs and pedipalps 

 possesses the following number of groups: Coxa i, trochanter 3, 

 femur 2, patella 3, tibia 3, metatarsus i, and occasionally the tarsus 

 I ; each cheliceron usually has 4, each pedicle 2, and only occasionally 

 is a group present on one of the spinnerets. The isolated slits not 

 only occur irregularly scattered on the joints of all the above-named 

 appendages, but also on the remaining mouth parts, on the sternum, 

 and a few on the ventral side of the abdomen. Thus it is seen that 

 the disposition of the lyriform organs is similar to that of Hicks' 

 vesicles ; however, the vesicles are situated at the proximal instead of 

 the distal ends of the joints and less seldom exist as isolated struct- 



