34 The Mechanism of Evolution in Leptinotaesa 



Third larval stage : In color and markings exactly like second stage, but with 

 body-color ivory white, becoming opaque or yellowed at pupation. Length at 

 maturity, 8 to 14 mm. (plate 1, fig. 3). 



Pupa: Pupate in ground, 0.5 to 6 inches below surface. Pupa, pale yellow 

 white, with spiracula spots very small. Duration of pupal stage, 10 to 20 days, 

 average 12 days. 



Length of larval period: Eange 20 to 42 days, average 27. 



Length of ontogeny: On average 49 days, range 30 to 80 days. The larval 

 stages of L. undecimlineata Stal described by Duges are not of this form, but of 

 L. diversa, which occurs (rarely) at the location where Duges obtained his 

 material near Guanajuato. 



Geographical Distbibtjtion. 



In its distribution this species as now limited is confined largely to the 

 savannahs and lower foot-hills and valleys about the Gulf of Campeche (plate 

 3 ) . I have included here only citation of localities where there is absolute cer- 

 tainty of the correctness of the determination. Many older records, even when 

 the material has been examined, are of no value, owing to poor preservation, 

 and can not be corrected. The records of localities submitted apply only to the 

 form as here limited, and while further information would no doubt change the 

 range and perhaps the relation of these closely placed species, nevertheless the 

 data given here is for a single form, irrespective of its systematic value. I have 

 found it at Campeche (near the city) at Esperanza, Tenabo, state of Campeche ; 

 Frontera, Chilapa, San Juan Bautista, Embarcadero, Huimanguillo, state of 

 Tabasco; Coatzacoalcos, Minatilan, Hidalgotilan, Tortugas, Santa Lucretia, 

 Medias Aguas, San Juan Evangelista, in the valley of Eio Coatzacoalcos, and in 

 many other unnamed localities in the same valley; Tlacotalpam, Achotal, San 

 Marcos, Teschoacan, Los ISTarancos, Chirpo, Perez, El Hule, Tuxtepec, Tierra 

 Blanca, Tepextempa, Motzorongo, Vista Hermosa, Agua Fria, and many other 

 localities in the valley of the Rio Papalaopan and its tributaries; Vera Cruz 

 (near the city), Paso del Macho, Camaron, Misantla — all in the state of Vera 

 Cruz. At all of these localities I have seen this species in all of its stages, and 

 at all of the localities the characters were uniform and constant. 



Habits and Ecology. 



An adequate general account of the habits and ecology of this species is given 

 in my 1906 report (Carnegie Inst. Wash. Pub. 48, pages 14 to 16). 



Source of Material. 



The living material for the various cultures and experiments described herein 

 came in the main from Tierra Blanca, San Marcos, and Coatzacoalcos. 



(fl) The location at Tierra Blanca, Vera Cruz, Mexico, 3 kilometers SW. by 

 W. of the railroad station is on the Coastal Plain at an altitude of 200 feet upon 

 a flat and typical tropical savannah, with an open, park-like, thorn-forest, and 

 poorly developed fringing forest along the water-courses. Well-developed wet 

 (June to January) and dry (January to May) seasons occur here, and the 

 activities of the beetles follow closely the climatic cycle. All material for experi- 

 mental purposes has been gathered from a restricted locality on the edge of a 

 small stream. Stocks were obtained as follows: No. 700 in August 1903; 

 No. 701 in May 1904; No. 702 in July 1906; No. 703 in June 1908. 



