author's abstract of this paper issued 

 by the bibliographic service, april 5 



THE OLFACTORY SENSE OF ORTHOPTERA 



N. E. McINDOO 

 Bureau of Entomology, Washington, D. C. 



NINETY-TWO FIGURES 



CONTENTS 



Introduction and methods 405 



Morphology of the olfactory pores 407 



Disposition of pores in a grasshopper 407 



a. Pores on head 407 



b. Pores on thorax 409 



c. Pores on abdomen 411 



d. Pores on all six instars 412 



Disposition of pores in other Orthoptera 412 



a. Pores on head 413 



b. Pores on thorax 413 



c. Pores on abdomen 414 



d. Pores on first and last instars of croton-bug 414 



e. Family, generic, specific, and sexual variations 414 



Structures of pores in a grasshopper 415 



a. External structure 415 



b. Internal structure 419 



The antennal organs 421 



Responses to chemical stimuli 423 



Experiments with grasshoppers 423 



a. Unmutilated grasshoppers 423 



b. Grasshoppers with antennae severed through third segments .... 425 

 Experiments with crickets 425 



a. Unmutilated crickets 425 



b. Crickets with antennae severed through third segments 425 



Summary 426 



Literature cited 427 



INTRODUCTION AND METHODS 



The results herein recorded are a continuation of the writer's 

 investigations concerning the olfactory pores of insects. Up to 

 date, including the present results, these organs have been care- 

 fully studied in Hymenoptera, Coleoptera, Lepidoptera, Diptera, 



405 



