1919] Mclndoo: Olfactory Sense 71 



MORPHOLOGY OF OLFACTORY PORES OR PUNCTURES. 



The preceding pages show that lepidopterous larvae respond 

 to chemical stimuli, and the following pages will show that 

 these larvae have organs suitable for the reception of chemical 

 stimuli, but no experiments were performed to determine the 

 function of these organs which were first called olfactory pores 

 by the writer (1914a). The same type of organs seems to be 

 common to all adult insects and the writer has proved exper- 

 imentally that they receive chemical stimuli in Hymenoptera 

 (1914b) and Coleoptera (1915). They have also proved to be 

 common to all of the coleopterous and lepidopterous larvas yet 

 examined by the writer, and now for several years systematists 

 have known them in lepidopterous larvae as "punctures." The 

 writer (1918) has recently described the external and internal 

 anatomy of them in a coleopterous larva of the 'fig-eater,' 

 Allorhina {Cotinis) nitida L. 



1. Disposition of Pores or Punctures. 



In making a comparative study of the distribution and 

 number of these pores in lepidopterous larvae, 30 species, 

 belonging to 28 genera and representing 20 families have been 

 used. Most of these were collected by the writer and the 

 remainder were kindly furnished by Mr. Carl Heinrich who 

 identified all of them. With a few exceptions, the writer has 

 adopted Mr. Heinrich's (1916, 1918) nomenclature given to 

 most of the punctures present on the head capsule and at the 

 suggestions of Messrs. Heinrich and Busck he has formulated 

 new names for those pores not already named. The various 

 parts of the anatomy on which these pores occur were verified by 

 Dr. Adam Boving; the three foregoing mentioned men also 

 belong to the Bureau of Entomology. 



In most cases only one specimen of each species was exam- 

 ined, and consequently, owing to unfavorable mounts and the 

 lack of sufficient material, the total number of pores recorded 

 can not be regarded as accurate. Since the army worm was 

 the most favorable material at hand, several specimens of it 

 were treated with caustic potash and the pores on it have been 

 studied and drawn in detail. 



The description of them will be given first and then will 

 follow a brief account of those in other species. 



