PREFACE. 



Damage by the boll weevil has brought into prominence many other 

 insects which attack the cotton plant, the work of which has been 

 largely overlooked. Among the most important of these minor 

 insects are various species of plant-bugs. Many of these have been 

 known as enemies of the cotton plant for some years, but they have 

 received only slight attention from economic entomologists. When 

 their damage is added to the injury done by the cotton boll weevil, 

 still further reducing the crop, they become of such importance that 

 full knowledge of their habits and life history is demanded. The 

 studies upon which this bulletin is based were conducted to add to 

 our knowledge of the biology of an important group of insect pests 

 and of the most practical and efficient methods by which they may 

 be controlled. 



The plant-bugs with which this bulletin deals, in addition to destroy- 

 ing many cotton bolls and squares, cause more or less staining of the 

 fiber, thus reducing the quality. A large portion of the so-called 

 '' spotted cotton," which everywhere suffers a considerable reduction in 

 price below unspotted cotton, is due to the work of plant-bugs. The 

 damage is not confined to any restricted areas, though different species 

 of bugs occur in different parts of the cotton belt. Therefore the 

 damage that is done by these insect pests every year is by no means 

 inconsiderable. 



The work accomplished by Doctor Morrill and reported on in this 

 bulletin grew out of an investigation of the Mexican conchuela 

 (Pentatoma ligata Say) in northern Mexico. An opportunity was 

 there afforded for a rather careful study of the life history and habits 

 of a representative of the large family of plant-bugs. This was 

 followed by investigations of the same species in western Texas and 

 of other species in other localities. As a result Doctor Morrill's work 

 gives rather complete knowledge of insects the work of which 

 will assume new importance as the area of boll-weevil infestation 

 continues to increase in the United States. 



For valuable notes and data on various subjects concerning the 

 conchuela, and especially on its seasonal history, for hearty coopera- 

 tion in experimental work, and for the facilities which aided in 



5 



