Materials, Their Taxonomy and Natural History 47 



Tlascalo in the State of Tlascala ; Mexico City, Guadalupe, Tacubaya, Tacuba, 

 Santa Fe, San Angel, Tlalpam, Tlalnepantla, Texcoco, and Mixeoco in the 

 Valley of Mexico. 



Source of Material. 



The stocks for different experimental purposes have been derived as follows, 

 and in the body of the paper will be referred to according to the name of the 

 location from which they were derived. 



(a) Guadalupe stock: From a location on the shore of Lake Texcoco, on an 

 old shore-line east of the Shrine of Guadalupe. Location described. Tower 

 (1906), plates 5 and 6, pages 18 to 20. Improvement and cultivation destroyed 

 this location in 1907-8. Stocks were obtained as follows: No. 500 in July 

 1903; No. 501 in May 1904; No. 503 in August 1904; No. 503 in July 1905; 

 No. 504 in August 1908. 



(&) Chapultepec stock: From the plain to north of the Cerro Chapultepec, 

 in waste places and pastures; is fast being built up and the location is now 

 nearly obliterated. Stocks were obtained as follows : No. 540 in August 1903 ; 

 No. 541 in May 1904; No. 542 in July 1905 ; No. 543 in August 1906 ; No. 544 

 in June 1909 ; No. 545 in August 1908. 



(c) Tlalnepantla stock: From west shore of Lake Xico, near Tlalnepantla. 

 Stocks were obtained as follows: No. 510 in August 1903; No. 511 in May 

 1904; No. 513 in June 1907. 



(d) Puebla stock: From open plain to northeast of the city, about one-half 

 mile north of Cerro de Guadalupe. An open rolling plain, more or less culti- 

 vated; well drained. Stocks were obtained as follows: No. 515 in August 

 1903; No. 516 in May 1904; No. 517 in June 1905; No. 518 in August 1906; 

 No. 519 in June 1909*; No. 520 in June 1910. 



(e) Apam stock: From the open plain of Apam, on the edge of a wet-season 

 lake about a mile northeast of the town. Stocks were obtained as follows : No. 

 525 in August 1904 ; No. 526 in August 1905 ; No. 527 in June 1909. 



(/) Chalcicotnula stock: On the road from Chalcicomula to San Andres 

 Chalcicomula, a mile from the plaza ; location is a cold, dry upland savannah. 

 Stocks were obtained as follows: No. 530 in July 1904; No. 531 in June 

 1905 ; No. 533 in August 1906 ; No. 533 in June 1908 ; No. 534 in June 1910. 



These stocks and several others have been tested, analyzed, and made the 

 basis of experiments in many lines, and the data of these analyses have entered 

 largely into the understanding of the real nature of this species as it is found 

 in nature, and without the analysis of the laboratory a correct understanding 

 would be impossible. 



Recurrent Mutation L. multit^niata-melanothorax Stal. 

 This form has hitherto been recorded as a species and is so included in all 

 lists and collections. In 1906 I was noncommittal as to its status, but further 

 study shows in the clearest possible manner that it is not a species, but a 

 recurrent mutant, as here recorded. 



Myocoryna mulanothorax Stai, 1859. Ofv. af. k. Vet. Forh., p. 317.7. 



Chrysomela melanothorax St^l, 1862. Monog. Chrys. Am., p. 166. 



Leptinotarsa melanothorax Stai in Gemminger et Harold, 1874, Catalog. 

 Coleop., t. IX, pt. 1, p. 3441; Jacoby, 1883, Biol. Centr. Am., vol. VI, pt. 1, 

 p. 234, suppl., p. 254; Tower, 1906, Inves. Evol. Chrys. Beetles, Genus 

 Lept, Carnegie Inst. Wash., Pub. No. 48, p. 720. 



