24 PLANT-BUGS INJURIOUS TO COTTON BOLLS. 



with the note that the species was injuring cotton in the Laguna 

 District of Mexico at San Pedro de la Colonia, State of Coahuila. 

 In March, 1904, the author was directed by the Entomologist to in- 

 vestigate a reported partial destruction of the cotton crop by an un- 

 known pest in the Laguna District of Mexico. The specific report 

 emanated from a large plantation of between 25,000 and 30,000 acres 

 of cultivated land located in the northern portion of the Laguna 

 District, the headquarters being at Tlahualilo, State of Durango. 

 At the season of the year when the first visit was made, although the 

 cotton stalks were still standing in the fields, it was impossible to 

 establish positively the relationship between the conchuela and the 

 large number of ruined bolls present everywhere on the plantation. 

 The second visit to Tlahualilo from August 30 to September 8, 1904, 

 resulted in this point being definitely determined as well as in the 

 procuring of considerable information concerning the insect and its 

 work. The details of these preliminary investigations were reported 

 on in a previous bulletin of this Bureau.^ 



The investigations were continued in 1905 at Tlahualilo, where the 

 author of this report spent the month of July and a week in the early 

 part of December. 



The conchuela has recently become known as a pest in western 

 Texas, where, in 1904 and 1905, near Barstow, it occasioned con- 

 siderable loss to seed crops of alfalfa, and in the latter season proved, 

 in addition, its destructiveness to miscellaneous crops, including 

 peaches, grapes, peas, and other garden products. The report of the 

 investigation of this unexpected outbreak has been published under 

 a separate title. ^ 



DISTRIBUTION. 



The distribution of Pentatoma ligata is a wide one, the species 

 occurring rarely in the eastern half of the United States, and with 

 much more frequency in the arid and semiarid regions of the Western 

 States and Mexico. It is probably of considerable significance that 

 hitherto locaHties where this species has been found to occur in large 

 numbers have been situated in the Lower Sonoran faunal region of 

 the Lower Austral zone. In Texas miscellaneous collections for three 

 years by members of the Bureau of Entomology engaged in cotton 

 boll weevil investigations have not included a single specimen of 

 Pentatoma ligata taken east of the semiarid region or approximately 

 the ninety-eighth degree of longitude. A single specimen in the 

 collection at the office of the Texas state entomologist bears the 

 label Beeville, Tex., which is situated between the ninety-seventh 

 and the ninety-eighth degrees of longitude and is the easternmost 



« BuL 54, Bur. Ent., U. S. Dept. Agr., pp. 18-34, 1905. 

 t>Bu\. 64, Pt. I, Bur. Ent., U. S. Dept. Agr., 1907. 



