2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



INTRODUCTION 



Since the early days of forest entomology, the superfamily of Sco- 

 lytoidea has always fascinated the investigators working on forest in- 

 sects. The destructive work of some of them, in spite of their relatively 

 small size, and also their peculiar habits were undoubtedly the reasons 

 for this extraordinary interest. However, with the cultivation of such 

 crops as coffee, tea, and other subtropical crops these insects have 

 become of greater interest to the economic entomologist in general. 



The literature dealing with the nomenclature and the bionomics of 

 species belonging to this superfamily is enormous. Several attempts 

 have been made to construct a classification based on morphological 

 characters. Other investigations were undertaken to homologize cer- 

 tain structures to act as a guide for the proper placing of the genera 

 throughout the group. In this connection it is necessary to mention 

 only a few authors, such as Lindemann, Eichhoff, Verhoeff , Hagedorn, 

 Nuesslin, Fuchs, and Hopkins. However, up to the present there is 

 comparatively little known in regard to the morphological, histological, 

 and physiological details. There has been practically nothing published 

 concerning the muscle structure, the respiratory system (with the ex- 

 ception of the number and position of the spiracles in the adults and 

 in a few cases in the larvae), the circulatory system, the sensory 

 organs, the blood, the nervous system, the metamorphosis, the his- 

 tology, etc. 



Concerning the control of the more important primary forest pests, 

 hundreds of recommendations have been made by different authorities. 

 However, all that have been made up to the present have failed to give 

 satisfactory control under all conditions. The recent ideas of Seit- 

 ner (53), used and enlarged by the Russian investigators Golov- 

 janko (55) and Iljinsky (60), seem, in conjunction with more careful 

 forest management, to represent the most hopeful direction for future 

 work. Undoubtedly even these modern outlooks will require enor- 

 mous further work to throw light upon the laws by which bark-beetle 

 outbreaks are governed. After solving these problems the time will 

 probably come when preventive measures will replace the expensive 

 and often useless control methods of our day. 



The following investigations are a tentative endeavor leading to 

 a more intensive monograph of the genus Gnathotrichus Eichhoff. 

 They have been carried out as a private study. 



This first paper covers the chitinous skeleton of the adult, pupa and 

 larva, the structure of the digestive system and the reproductive or- 

 gans of the adult and larva. It is hoped later to publish tv/o more 



